diff --git a/CHANGES.md b/CHANGES.md
index d95c477fd..7bec65640 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,4 @@
-# Changes
+# Changelog
 
 Changelogs are kept separately for each crate in this repo.
 
diff --git a/actix-files/CHANGES.md b/actix-files/CHANGES.md
index f0234b561..4d4c790e8 100644
--- a/actix-files/CHANGES.md
+++ b/actix-files/CHANGES.md
@@ -1,6 +1,13 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+- Add support for streaming audio files by setting the `content-disposition` header `inline` instead of `attachement`. [#2645]
+
+[#2645]: https://github.com/actix/actix-web/pull/2645
+
+
+## 0.6.0 - 2022-02-25
+- No significant changes since `0.6.0-beta.16`.
 
 
 ## 0.6.0-beta.16 - 2022-01-31
diff --git a/actix-files/Cargo.toml b/actix-files/Cargo.toml
index a006df953..e7e6aea23 100644
--- a/actix-files/Cargo.toml
+++ b/actix-files/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-files"
-version = "0.6.0-beta.16"
+version = "0.6.0"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "fakeshadow <24548779@qq.com>",
@@ -22,10 +22,10 @@ path = "src/lib.rs"
 experimental-io-uring = ["actix-web/experimental-io-uring", "tokio-uring"]
 
 [dependencies]
-actix-http = "3.0.0-rc.3"
+actix-http = "3"
 actix-service = "2"
 actix-utils = "3"
-actix-web = { version = "4.0.0-rc.3", default-features = false }
+actix-web = { version = "4", default-features = false }
 
 askama_escape = "0.10"
 bitflags = "1"
@@ -44,5 +44,5 @@ tokio-uring = { version = "0.2", optional = true, features = ["bytes"] }
 [dev-dependencies]
 actix-rt = "2.2"
 actix-test = "0.1.0-beta.13"
-actix-web = "4.0.0-rc.3"
+actix-web = "4.0.0"
 tempfile = "3.2"
diff --git a/actix-files/README.md b/actix-files/README.md
index 8ac80860e..3c4d4443c 100644
--- a/actix-files/README.md
+++ b/actix-files/README.md
@@ -3,11 +3,11 @@
 > Static file serving for Actix Web
 
 [![crates.io](https://img.shields.io/crates/v/actix-files?label=latest)](https://crates.io/crates/actix-files)
-[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0-beta.16)](https://docs.rs/actix-files/0.6.0-beta.16)
+[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0)](https://docs.rs/actix-files/0.6.0)
 [![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
 ![License](https://img.shields.io/crates/l/actix-files.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-files/0.6.0-beta.16/status.svg)](https://deps.rs/crate/actix-files/0.6.0-beta.16)
+[![dependency status](https://deps.rs/crate/actix-files/0.6.0/status.svg)](https://deps.rs/crate/actix-files/0.6.0)
 [![Download](https://img.shields.io/crates/d/actix-files.svg)](https://crates.io/crates/actix-files)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
diff --git a/actix-files/src/chunked.rs b/actix-files/src/chunked.rs
index 3ee2ee072..241b4dccb 100644
--- a/actix-files/src/chunked.rs
+++ b/actix-files/src/chunked.rs
@@ -81,7 +81,7 @@ async fn chunked_read_file_callback(
 ) -> Result<(File, Bytes), Error> {
     use io::{Read as _, Seek as _};
 
-    let res = actix_web::rt::task::spawn_blocking(move || {
+    let res = actix_web::web::block(move || {
         let mut buf = Vec::with_capacity(max_bytes);
 
         file.seek(io::SeekFrom::Start(offset))?;
@@ -94,8 +94,7 @@ async fn chunked_read_file_callback(
             Ok((file, Bytes::from(buf)))
         }
     })
-    .await
-    .map_err(|_| actix_web::error::BlockingError)??;
+    .await??;
 
     Ok(res)
 }
diff --git a/actix-files/src/named.rs b/actix-files/src/named.rs
index baf9b5531..6f3c6e1c8 100644
--- a/actix-files/src/named.rs
+++ b/actix-files/src/named.rs
@@ -96,18 +96,18 @@ impl NamedFile {
     ///
     /// # Examples
     /// ```ignore
+    /// use std::{
+    ///     io::{self, Write as _},
+    ///     env,
+    ///     fs::File
+    /// };
     /// use actix_files::NamedFile;
-    /// use std::io::{self, Write};
-    /// use std::env;
-    /// use std::fs::File;
     ///
-    /// fn main() -> io::Result<()> {
-    ///     let mut file = File::create("foo.txt")?;
-    ///     file.write_all(b"Hello, world!")?;
-    ///     let named_file = NamedFile::from_file(file, "bar.txt")?;
-    ///     # std::fs::remove_file("foo.txt");
-    ///     Ok(())
-    /// }
+    /// let mut file = File::create("foo.txt")?;
+    /// file.write_all(b"Hello, world!")?;
+    /// let named_file = NamedFile::from_file(file, "bar.txt")?;
+    /// # std::fs::remove_file("foo.txt");
+    /// Ok(())
     /// ```
     pub fn from_file<P: AsRef<Path>>(file: File, path: P) -> io::Result<NamedFile> {
         let path = path.as_ref().to_path_buf();
@@ -128,7 +128,7 @@ impl NamedFile {
             let ct = from_path(&path).first_or_octet_stream();
 
             let disposition = match ct.type_() {
-                mime::IMAGE | mime::TEXT | mime::VIDEO => DispositionType::Inline,
+                mime::IMAGE | mime::TEXT | mime::AUDIO | mime::VIDEO => DispositionType::Inline,
                 mime::APPLICATION => match ct.subtype() {
                     mime::JAVASCRIPT | mime::JSON => DispositionType::Inline,
                     name if name == "wasm" => DispositionType::Inline,
diff --git a/actix-http-test/Cargo.toml b/actix-http-test/Cargo.toml
index 2fb4a4f77..e2a2bcc3d 100644
--- a/actix-http-test/Cargo.toml
+++ b/actix-http-test/Cargo.toml
@@ -51,5 +51,5 @@ tls-openssl = { version = "0.10.9", package = "openssl", optional = true }
 tokio = { version = "1.8.4", features = ["sync"] }
 
 [dev-dependencies]
-actix-web = { version = "4.0.0-rc.3", default-features = false, features = ["cookies"] }
-actix-http = "3.0.0-rc.3"
+actix-web = { version = "4.0.0", default-features = false, features = ["cookies"] }
+actix-http = "3.0.0"
diff --git a/actix-http/CHANGES.md b/actix-http/CHANGES.md
index c8581c0b5..d73e8522f 100644
--- a/actix-http/CHANGES.md
+++ b/actix-http/CHANGES.md
@@ -3,6 +3,297 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 3.0.0 - 2022-02-25
+### Dependencies
+- Updated `actix-*` to Tokio v1-based versions. [#1813]
+- Updated `bytes` to `1.0`. [#1813]
+- Updated `h2` to `0.3`. [#1813]
+- Updated `rustls` to `0.20.0`. [#2414]
+- Updated `language-tags` to `0.3`.
+- Updated `tokio` to `1`.
+
+### Added
+- Crate Features:
+  - `ws`; disabled by default. [#2618]
+  - `http2`; disabled by default. [#2618]
+  - `compress-brotli`; disabled by default. [#2618]
+  - `compress-gzip`; disabled by default. [#2618]
+  - `compress-zstd`; disabled by default. [#2618]
+- Functions:
+  - `body::to_bytes` for async collecting message body into Bytes. [#2158]
+- Traits:
+  - `TryIntoHeaderPair`; allows using typed and untyped headers in the same methods. [#1869]
+- Types:
+  - `body::BoxBody`; a boxed message body with boxed errors. [#2183]
+  - `body::EitherBody` enum. [#2468]
+  - `body::None` struct. [#2468]
+  - Re-export `http` crate's `Error` type as `error::HttpError`. [#2171]
+- Variants:
+  - `ContentEncoding::Zstd` along with . [#2244]
+  - `Protocol::Http3` for future compatibility and also mark `#[non_exhaustive]`. [00ba8d55]
+- Methods:
+  - `ContentEncoding::to_header_value()`. [#2501]
+  - `header::QualityItem::{max, min}()`. [#2486]
+  - `header::QualityItem::zero()` that uses `Quality::ZERO`. [#2501]
+  - `HeaderMap::drain()` as an efficient draining iterator. [#1964]
+  - `HeaderMap::len_keys()` has the behavior of the old `len` method. [#1964]
+  - `MessageBody::boxed` trait method for wrapping boxing types efficiently. [#2520]
+  - `MessageBody::try_into_bytes` trait method, with default implementation, for optimizations on body types that complete in exactly one poll. [#2522]
+  - `Request::conn_data()`. [#2491]
+  - `Request::take_conn_data()`. [#2491]
+  - `Request::take_req_data()`. [#2487]
+  - `Response::{ok, bad_request, not_found, internal_server_error}()`. [#2159]
+  - `Response::into_body()` that consumes response and returns body type. [#2201]
+  - `Response::map_into_boxed_body()`. [#2468]
+  - `ResponseBuilder::append_header()` method which allows using typed and untyped headers. [#1869]
+  - `ResponseBuilder::insert_header()` method which allows using typed and untyped headers. [#1869]
+  - `ResponseHead::set_camel_case_headers()`. [#2587]
+  - `TestRequest::insert_header()` method which allows using typed and untyped headers. [#1869]
+- Implementations:
+  - Implement `Clone for ws::HandshakeError`. [#2468]
+  - Implement `Clone` for `body::AnyBody<S> where S: Clone`. [#2448]
+  - Implement `Clone` for `RequestHead`. [#2487]
+  - Implement `Clone` for `ResponseHead`. [#2585]
+  - Implement `Copy` for `QualityItem<T> where T: Copy`. [#2501]
+  - Implement `Default` for `ContentEncoding`. [#1912]
+  - Implement `Default` for `HttpServiceBuilder`. [#2611]
+  - Implement `Default` for `KeepAlive`. [#2611]
+  - Implement `Default` for `Response`. [#2201]
+  - Implement `Default` for `ws::Codec`. [#1920]
+  - Implement `Display` for `header::Quality`. [#2486]
+  - Implement `Eq` for `header::ContentEncoding`. [#2501]
+  - Implement `ExactSizeIterator` and `FusedIterator` for all `HeaderMap` iterators. [#2470]
+  - Implement `From<Duration>` for `KeepAlive`. [#2611]
+  - Implement `From<Option<Duration>>` for `KeepAlive`. [#2611]
+  - Implement `From<Vec<u8>>` for `Response<Vec<u8>>`. [#2625]
+  - Implement `FromStr` for `ContentEncoding`. [#1912]
+  - Implement `Header` for `ContentEncoding`. [#1912]
+  - Implement `IntoHeaderValue` for `ContentEncoding`. [#1912]
+  - Implement `IntoIterator` for `HeaderMap`. [#1964]
+  - Implement `MessageBody` for `bytestring::ByteString`. [#2468]
+  - Implement `MessageBody` for `Pin<Box<T>> where T: MessageBody`. [#2152]
+- Misc:
+  - Re-export `StatusCode`, `Method`, `Version` and `Uri` at the crate root. [#2171]
+  - Re-export `ContentEncoding` and `ConnectionType` at the crate root. [#2171]
+  - `Quality::ZERO` associated constant equivalent to `q=0`. [#2501]
+  - `header::Quality::{MAX, MIN}` associated constants equivalent to `q=1` and `q=0.001`, respectively. [#2486]
+  - Timeout for canceling HTTP/2 server side connection handshake. Configurable with `ServiceConfig::client_timeout`; defaults to 5 seconds. [#2483]
+  - `#[must_use]` for `ws::Codec` to prevent subtle bugs. [#1920]
+
+### Changed
+- Traits:
+  - Rename `IntoHeaderValue => TryIntoHeaderValue`. [#2510]
+  - `MessageBody` now has an associated `Error` type. [#2183]
+- Types:
+  - `Protocol` enum is now marked `#[non_exhaustive]`.
+  - `error::DispatcherError` enum is now marked `#[non_exhaustive]`. [#2624]
+  - `ContentEncoding` is now marked `#[non_exhaustive]`. [#2377]
+  - Error enums are marked `#[non_exhaustive]`. [#2161]
+  - Rename `PayloadStream` to `BoxedPayloadStream`. [#2545]
+  - The body type parameter of `Response` no longer has a default. [#2152]
+- Enum Variants:
+  - Rename `ContentEncoding::{Br => Brotli}`. [#2501]
+  - `Payload` inner fields are now named. [#2545]
+  - `ws::Message::Text` now contains a `bytestring::ByteString`. [#1864]
+- Methods:
+  - Rename `ServiceConfig::{client_timer_expire => client_request_deadline}`. [#2611]
+  - Rename `ServiceConfig::{client_disconnect_timer => client_disconnect_deadline}`. [#2611]
+  - Rename `h1::Codec::{keepalive => keep_alive}`. [#2611]
+  - Rename `h1::Codec::{keepalive_enabled => keep_alive_enabled}`. [#2611]
+  - Rename `h1::ClientCodec::{keepalive => keep_alive}`. [#2611]
+  - Rename `h1::ClientPayloadCodec::{keepalive => keep_alive}`. [#2611]
+  - Rename `header::EntityTag::{weak => new_weak, strong => new_strong}`. [#2565]
+  - Rename `TryIntoHeaderValue::{try_into => try_into_value}` to avoid ambiguity with std `TryInto` trait. [#1894]
+  - Deadline methods in `ServiceConfig` now return `std::time::Instant`s instead of Tokio's wrapper type. [#2611]
+  - Places in `Response` where `ResponseBody<B>` was received or returned now simply use `B`. [#2201]
+  - `encoding::Encoder::response` now returns `AnyBody<Encoder<B>>`. [#2448]
+  - `Extensions::insert` returns replaced item. [#1904]
+  - `HeaderMap::get_all` now returns a `std::slice::Iter`. [#2527]
+  - `HeaderMap::insert` now returns iterator of removed values. [#1964]
+  - `HeaderMap::len` now returns number of values instead of number of keys. [#1964]
+  - `HeaderMap::remove` now returns iterator of removed values. [#1964]
+  - `ResponseBuilder::body(B)` now returns `Response<EitherBody<B>>`. [#2468]
+  - `ResponseBuilder::content_type` now takes an `impl TryIntoHeaderValue` to support using typed `mime` types. [#1894]
+  - `ResponseBuilder::finish()` now returns `Response<EitherBody<()>>`. [#2468]
+  - `ResponseBuilder::json` now takes `impl Serialize`. [#2052]
+  - `ResponseBuilder::message_body` now returns a `Result`. [#2201]∑
+  - `ServiceConfig::keep_alive` now returns a `KeepAlive`. [#2611]
+  - `ws::hash_key` now returns array. [#2035]
+- Trait Implementations:
+  - Implementation of `Stream` for `Payload` no longer requires the `Stream` variant be `Unpin`. [#2545]
+  - Implementation of `Future` for `h1::SendResponse` no longer requires the body type be `Unpin`. [#2545]
+  - Implementation of `Stream` for `encoding::Decoder` no longer requires the stream type be `Unpin`. [#2545]
+  - Implementation of `From` for error types now return a `Response<BoxBody>`. [#2468]
+- Misc:
+  - `header` module is now public. [#2171]
+  - `uri` module is now public. [#2171]
+  - Request-local data container is no longer part of a `RequestHead`. Instead it is a distinct part of a `Request`. [#2487]
+  - All error trait bounds in server service builders have changed from `Into<Error>` to `Into<Response<BoxBody>>`. [#2253]
+  - All error trait bounds in message body and stream impls changed from `Into<Error>` to `Into<Box<dyn std::error::Error>>`. [#2253]
+  - Guarantee ordering of `header::GetAll` iterator to be same as insertion order. [#2467]
+  - Connection data set through the `on_connect_ext` callbacks is now accessible only from the new `Request::conn_data()` method. [#2491]
+  - Brotli (de)compression support is now provided by the `brotli` crate. [#2538]
+  - Minimum supported Rust version (MSRV) is now 1.54.
+
+### Fixed
+- A `Vary` header is now correctly sent along with compressed content. [#2501]
+- HTTP/1.1 dispatcher correctly uses client request timeout. [#2611]
+- Fixed issue where handlers that took payload but then dropped without reading it to EOF it would cause keep-alive connections to become stuck. [#2624]
+- `ContentEncoding`'s `Identity` variant can now be parsed from a string. [#2501]
+- `HttpServer::{listen_rustls(), bind_rustls()}` now honor the ALPN protocols in the configuration parameter. [#2226]
+- Remove unnecessary `Into<Error>` bound on `Encoder` body types. [#2375]
+- Remove unnecessary `Unpin` bound on `ResponseBuilder::streaming`. [#2253]
+- `BodyStream` and `SizedStream` are no longer restricted to `Unpin` types. [#2152]
+- Fixed slice creation pointing to potential uninitialized data on h1 encoder. [#2364]
+- Fixed quality parse error in Accept-Encoding header. [#2344]
+
+### Removed
+- Crate Features:
+  - `compress` feature. [#2065]
+  - `cookies` feature. [#2065]
+  - `trust-dns` feature. [#2425]
+  - `actors` optional feature and trait implementation for `actix` types. [#1969]
+- Functions:
+  - `header::qitem` helper. Replaced with `header::QualityItem::max`. [#2486]
+- Types:
+  - `body::Body`; replaced with `EitherBody` and `BoxBody`. [#2468]
+  - `body::ResponseBody`. [#2446]
+  - `ConnectError::SslHandshakeError` and re-export of `HandshakeError`. Due to the removal of this type from `tokio-openssl` crate. OpenSSL handshake error now returns `ConnectError::SslError`. [#1813]
+  - `error::Canceled` re-export. [#1994]
+  - `error::Result` type alias. [#2201]
+  - `error::BlockingError` [#2660]
+  - `InternalError` and all the error types it constructed were moved up to `actix-web`. [#2215]
+  - Typed HTTP headers; they have moved up to `actix-web`. [2094]
+  - Re-export of `http` crate's `HeaderMap` types in addition to ours. [#2171]
+- Enum Variants:
+  - `body::BodySize::Empty`; an empty body can now only be represented as a `Sized(0)` variant. [#2446]
+  - `ContentEncoding::Auto`. [#2501]
+  - `EncoderError::Boxed`. [#2446]
+- Methods:
+  - `ContentEncoding::is_compression()`. [#2501]
+  - `h1::Payload::readany()`. [#2545]
+  - `HttpMessage::cookie[s]()` trait methods. [#2065]
+  - `HttpServiceBuilder::new()`; use `default` instead. [#2611]
+  - `on_connect` (previously deprecated) methods have been removed; use `on_connect_ext`. [#1857]
+  - `Response::build_from()`. [#2159]
+  - `Response::error()` [#2205]
+  - `Response::take_body()` and old `Response::into_body()` method that casted body type. [#2201]
+  - `Response`'s status code builders. [#2159]
+  - `ResponseBuilder::{if_true, if_some}()` (previously deprecated). [#2148]
+  - `ResponseBuilder::{set, set_header}()`; use `ResponseBuilder::insert_header()`. [#1869]
+  - `ResponseBuilder::extensions[_mut]()`. [#2585]
+  - `ResponseBuilder::header()`; use `ResponseBuilder::append_header()`. [#1869]
+  - `ResponseBuilder::json()`. [#2148]
+  - `ResponseBuilder::json2()`. [#1903]
+  - `ResponseBuilder::streaming()`. [#2468]
+  - `ResponseHead::extensions[_mut]()`. [#2585]
+  - `ServiceConfig::{client_timer, keep_alive_timer}()`. [#2611]
+  - `TestRequest::with_hdr()`; use `TestRequest::default().insert_header()`. [#1869]
+  - `TestRequest::with_header()`; use `TestRequest::default().insert_header()`. [#1869]
+- Trait implementations:
+  - Implementation of `Copy` for `ws::Codec`. [#1920]
+  - Implementation of `From<Option<usize>> for KeepAlive`; use `Duration`s instead. [#2611]
+  - Implementation of `From<serde_json::Value>` for `Body`. [#2148]
+  - Implementation of `From<usize> for KeepAlive`; use `Duration`s instead. [#2611]
+  - Implementation of `Future` for `Response`. [#2201]
+  - Implementation of `Future` for `ResponseBuilder`. [#2468]
+  - Implementation of `Into<Error>` for `Response<Body>`. [#2215]
+  - Implementation of `Into<Error>` for `ResponseBuilder`. [#2215]
+  - Implementation of `ResponseError` for `actix_utils::timeout::TimeoutError`. [#2127]
+  - Implementation of `ResponseError` for `CookieParseError`. [#2065]
+  - Implementation of `TryFrom<u16>` for `header::Quality`. [#2486]
+- Misc:
+  - `http` module; most everything it contained is exported at the crate root. [#2488]
+  - `cookies` module (re-export). [#2065]
+  - `client` module. Connector types now live in `awc`. [#2425]
+  - `error` field from `Response`. [#2205]
+  - `downcast` and `downcast_get_type_id` macros. [#2291]
+  - Down-casting for `MessageBody` types; use standard `Any` trait. [#2183]
+
+
+[#1813]: https://github.com/actix/actix-web/pull/1813
+[#1845]: https://github.com/actix/actix-web/pull/1845
+[#1857]: https://github.com/actix/actix-web/pull/1857
+[#1864]: https://github.com/actix/actix-web/pull/1864
+[#1869]: https://github.com/actix/actix-web/pull/1869
+[#1878]: https://github.com/actix/actix-web/pull/1878
+[#1894]: https://github.com/actix/actix-web/pull/1894
+[#1903]: https://github.com/actix/actix-web/pull/1903
+[#1904]: https://github.com/actix/actix-web/pull/1904
+[#1912]: https://github.com/actix/actix-web/pull/1912
+[#1920]: https://github.com/actix/actix-web/pull/1920
+[#1964]: https://github.com/actix/actix-web/pull/1964
+[#1969]: https://github.com/actix/actix-web/pull/1969
+[#1981]: https://github.com/actix/actix-web/pull/1981
+[#1994]: https://github.com/actix/actix-web/pull/1994
+[#2035]: https://github.com/actix/actix-web/pull/2035
+[#2052]: https://github.com/actix/actix-web/pull/2052
+[#2065]: https://github.com/actix/actix-web/pull/2065
+[#2094]: https://github.com/actix/actix-web/pull/2094
+[#2127]: https://github.com/actix/actix-web/pull/2127
+[#2148]: https://github.com/actix/actix-web/pull/2148
+[#2152]: https://github.com/actix/actix-web/pull/2152
+[#2158]: https://github.com/actix/actix-web/pull/2158
+[#2159]: https://github.com/actix/actix-web/pull/2159
+[#2161]: https://github.com/actix/actix-web/pull/2161
+[#2171]: https://github.com/actix/actix-web/pull/2171
+[#2183]: https://github.com/actix/actix-web/pull/2183
+[#2196]: https://github.com/actix/actix-web/pull/2196
+[#2201]: https://github.com/actix/actix-web/pull/2201
+[#2205]: https://github.com/actix/actix-web/pull/2205
+[#2215]: https://github.com/actix/actix-web/pull/2215
+[#2244]: https://github.com/actix/actix-web/pull/2244
+[#2250]: https://github.com/actix/actix-web/pull/2250
+[#2253]: https://github.com/actix/actix-web/pull/2253
+[#2291]: https://github.com/actix/actix-web/pull/2291
+[#2344]: https://github.com/actix/actix-web/pull/2344
+[#2364]: https://github.com/actix/actix-web/pull/2364
+[#2375]: https://github.com/actix/actix-web/pull/2375
+[#2377]: https://github.com/actix/actix-web/pull/2377
+[#2414]: https://github.com/actix/actix-web/pull/2414
+[#2425]: https://github.com/actix/actix-web/pull/2425
+[#2442]: https://github.com/actix/actix-web/pull/2442
+[#2446]: https://github.com/actix/actix-web/pull/2446
+[#2448]: https://github.com/actix/actix-web/pull/2448
+[#2456]: https://github.com/actix/actix-web/pull/2456
+[#2467]: https://github.com/actix/actix-web/pull/2467
+[#2468]: https://github.com/actix/actix-web/pull/2468
+[#2470]: https://github.com/actix/actix-web/pull/2470
+[#2474]: https://github.com/actix/actix-web/pull/2474
+[#2483]: https://github.com/actix/actix-web/pull/2483
+[#2486]: https://github.com/actix/actix-web/pull/2486
+[#2487]: https://github.com/actix/actix-web/pull/2487
+[#2488]: https://github.com/actix/actix-web/pull/2488
+[#2491]: https://github.com/actix/actix-web/pull/2491
+[#2497]: https://github.com/actix/actix-web/pull/2497
+[#2501]: https://github.com/actix/actix-web/pull/2501
+[#2510]: https://github.com/actix/actix-web/pull/2510
+[#2520]: https://github.com/actix/actix-web/pull/2520
+[#2522]: https://github.com/actix/actix-web/pull/2522
+[#2527]: https://github.com/actix/actix-web/pull/2527
+[#2538]: https://github.com/actix/actix-web/pull/2538
+[#2545]: https://github.com/actix/actix-web/pull/2545
+[#2565]: https://github.com/actix/actix-web/pull/2565
+[#2585]: https://github.com/actix/actix-web/pull/2585
+[#2587]: https://github.com/actix/actix-web/pull/2587
+[#2611]: https://github.com/actix/actix-web/pull/2611
+[#2618]: https://github.com/actix/actix-web/pull/2618
+[#2624]: https://github.com/actix/actix-web/pull/2624
+[#2625]: https://github.com/actix/actix-web/pull/2625
+[#2660]: https://github.com/actix/actix-web/pull/2660
+[00ba8d55]: https://github.com/actix/actix-web/commit/00ba8d55492284581695d824648590715a8bd386
+
+
+<details>
+<summary>3.0.0 Pre-Releases</summary>
+
+## 3.0.0-rc.4 - 2022-02-22
+### Fixed
+- Fix h1 dispatcher panic. [1ce58ecb]
+
+[1ce58ecb]: https://github.com/actix/actix-web/commit/1ce58ecb305c60e51db06e6c913b7a1344e229ca
+
+
 ## 3.0.0-rc.3 - 2022-02-16
 - No significant changes since `3.0.0-rc.2`.
 
@@ -98,7 +389,7 @@
 
 
 ## 3.0.0-beta.17 - 2021-12-27
-### Changes
+### Changed
 - `HeaderMap::get_all` now returns a `std::slice::Iter`. [#2527]
 - `Payload` inner fields are now named. [#2545]
 - `impl Stream` for `Payload` no longer requires the `Stream` variant be `Unpin`. [#2545]
@@ -321,7 +612,7 @@
 - `Response::{ok, bad_request, not_found, internal_server_error}`. [#2159]
 - Helper `body::to_bytes` for async collecting message body into Bytes. [#2158]
 
-### Changes
+### Changed
 - The type parameter of `Response` no longer has a default. [#2152]
 - The `Message` variant of `body::Body` is now `Pin<Box<dyn MessageBody>>`. [#2152]
 - `BodyStream` and `SizedStream` are no longer restricted to Unpin types. [#2152]
@@ -465,6 +756,8 @@
 [#1864]: https://github.com/actix/actix-web/pull/1864
 [#1878]: https://github.com/actix/actix-web/pull/1878
 
+</details>
+
 
 ## 2.2.2 - 2022-01-21
 ### Changed
diff --git a/actix-http/Cargo.toml b/actix-http/Cargo.toml
index 30ac4ce3a..751b820e8 100644
--- a/actix-http/Cargo.toml
+++ b/actix-http/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-http"
-version = "3.0.0-rc.3"
+version = "3.0.0"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "Rob Ede <robjtede@icloud.com>",
@@ -100,7 +100,7 @@ zstd = { version = "0.10", optional = true }
 actix-http-test = { version = "3.0.0-beta.13", features = ["openssl"] }
 actix-server = "2"
 actix-tls = { version = "3", features = ["openssl"] }
-actix-web = "4.0.0-rc.3"
+actix-web = "4.0.0"
 
 async-stream = "0.3"
 criterion = { version = "0.3", features = ["html_reports"] }
diff --git a/actix-http/README.md b/actix-http/README.md
index c1aae63e1..8d414a0fc 100644
--- a/actix-http/README.md
+++ b/actix-http/README.md
@@ -3,11 +3,11 @@
 > HTTP primitives for the Actix ecosystem.
 
 [![crates.io](https://img.shields.io/crates/v/actix-http?label=latest)](https://crates.io/crates/actix-http)
-[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0-rc.3)](https://docs.rs/actix-http/3.0.0-rc.3)
+[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0)](https://docs.rs/actix-http/3.0.0)
 [![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-http.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-http/3.0.0-rc.3/status.svg)](https://deps.rs/crate/actix-http/3.0.0-rc.3)
+[![dependency status](https://deps.rs/crate/actix-http/3.0.0/status.svg)](https://deps.rs/crate/actix-http/3.0.0)
 [![Download](https://img.shields.io/crates/d/actix-http.svg)](https://crates.io/crates/actix-http)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
diff --git a/actix-http/src/encoding/decoder.rs b/actix-http/src/encoding/decoder.rs
index 2ed7be899..06b672fd8 100644
--- a/actix-http/src/encoding/decoder.rs
+++ b/actix-http/src/encoding/decoder.rs
@@ -19,7 +19,7 @@ use zstd::stream::write::Decoder as ZstdDecoder;
 
 use crate::{
     encoding::Writer,
-    error::{BlockingError, PayloadError},
+    error::PayloadError,
     header::{ContentEncoding, HeaderMap, CONTENT_ENCODING},
 };
 
@@ -47,14 +47,17 @@ where
             ContentEncoding::Brotli => Some(ContentDecoder::Brotli(Box::new(
                 brotli::DecompressorWriter::new(Writer::new(), 8_096),
             ))),
+
             #[cfg(feature = "compress-gzip")]
             ContentEncoding::Deflate => Some(ContentDecoder::Deflate(Box::new(
                 ZlibDecoder::new(Writer::new()),
             ))),
+
             #[cfg(feature = "compress-gzip")]
             ContentEncoding::Gzip => Some(ContentDecoder::Gzip(Box::new(GzDecoder::new(
                 Writer::new(),
             )))),
+
             #[cfg(feature = "compress-zstd")]
             ContentEncoding::Zstd => Some(ContentDecoder::Zstd(Box::new(
                 ZstdDecoder::new(Writer::new()).expect(
@@ -98,8 +101,12 @@ where
 
         loop {
             if let Some(ref mut fut) = this.fut {
-                let (chunk, decoder) =
-                    ready!(Pin::new(fut).poll(cx)).map_err(|_| BlockingError)??;
+                let (chunk, decoder) = ready!(Pin::new(fut).poll(cx)).map_err(|_| {
+                    PayloadError::Io(io::Error::new(
+                        io::ErrorKind::Other,
+                        "Blocking task was cancelled unexpectedly",
+                    ))
+                })??;
 
                 *this.decoder = Some(decoder);
                 this.fut.take();
@@ -159,10 +166,13 @@ where
 enum ContentDecoder {
     #[cfg(feature = "compress-gzip")]
     Deflate(Box<ZlibDecoder<Writer>>),
+
     #[cfg(feature = "compress-gzip")]
     Gzip(Box<GzDecoder<Writer>>),
+
     #[cfg(feature = "compress-brotli")]
     Brotli(Box<brotli::DecompressorWriter<Writer>>),
+
     // We need explicit 'static lifetime here because ZstdDecoder need lifetime
     // argument, and we use `spawn_blocking` in `Decoder::poll_next` that require `FnOnce() -> R + Send + 'static`
     #[cfg(feature = "compress-zstd")]
diff --git a/actix-http/src/encoding/encoder.rs b/actix-http/src/encoding/encoder.rs
index 2f104ee8f..0c81ffe1b 100644
--- a/actix-http/src/encoding/encoder.rs
+++ b/actix-http/src/encoding/encoder.rs
@@ -23,7 +23,6 @@ use zstd::stream::write::Encoder as ZstdEncoder;
 use super::Writer;
 use crate::{
     body::{self, BodySize, MessageBody},
-    error::BlockingError,
     header::{self, ContentEncoding, HeaderValue, CONTENT_ENCODING},
     ResponseHead, StatusCode,
 };
@@ -173,7 +172,12 @@ where
 
             if let Some(ref mut fut) = this.fut {
                 let mut encoder = ready!(Pin::new(fut).poll(cx))
-                    .map_err(|_| EncoderError::Blocking(BlockingError))?
+                    .map_err(|_| {
+                        EncoderError::Io(io::Error::new(
+                            io::ErrorKind::Other,
+                            "Blocking task was cancelled unexpectedly",
+                        ))
+                    })?
                     .map_err(EncoderError::Io)?;
 
                 let chunk = encoder.take();
@@ -400,12 +404,11 @@ fn new_brotli_compressor() -> Box<brotli::CompressorWriter<Writer>> {
 #[derive(Debug, Display)]
 #[non_exhaustive]
 pub enum EncoderError {
+    /// Wrapped body stream error.
     #[display(fmt = "body")]
     Body(Box<dyn StdError>),
 
-    #[display(fmt = "blocking")]
-    Blocking(BlockingError),
-
+    /// Generic I/O error.
     #[display(fmt = "io")]
     Io(io::Error),
 }
@@ -414,7 +417,6 @@ impl StdError for EncoderError {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
         match self {
             EncoderError::Body(err) => Some(&**err),
-            EncoderError::Blocking(err) => Some(err),
             EncoderError::Io(err) => Some(err),
         }
     }
diff --git a/actix-http/src/error.rs b/actix-http/src/error.rs
index 52b953421..3fce0a60b 100644
--- a/actix-http/src/error.rs
+++ b/actix-http/src/error.rs
@@ -51,7 +51,7 @@ impl Error {
         Self::new(Kind::SendResponse)
     }
 
-    #[allow(unused)] // reserved for future use (TODO: remove allow when being used)
+    #[allow(unused)] // available for future use
     pub(crate) fn new_io() -> Self {
         Self::new(Kind::Io)
     }
@@ -108,8 +108,10 @@ pub(crate) enum Kind {
 
 impl fmt::Debug for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // TODO: more detail
-        f.write_str("actix_http::Error")
+        f.debug_struct("actix_http::Error")
+            .field("kind", &self.inner.kind)
+            .field("cause", &self.inner.cause)
+            .finish()
     }
 }
 
@@ -250,12 +252,6 @@ impl From<ParseError> for Response<BoxBody> {
     }
 }
 
-/// A set of errors that can occur running blocking tasks in thread pool.
-#[derive(Debug, Display, Error)]
-#[display(fmt = "Blocking thread pool is gone")]
-// TODO: non-exhaustive
-pub struct BlockingError;
-
 /// A set of errors that can occur during payload parsing.
 #[derive(Debug, Display)]
 #[non_exhaustive]
@@ -293,13 +289,13 @@ impl std::error::Error for PayloadError {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         match self {
             PayloadError::Incomplete(None) => None,
-            PayloadError::Incomplete(Some(err)) => Some(err as &dyn std::error::Error),
+            PayloadError::Incomplete(Some(err)) => Some(err),
             PayloadError::EncodingCorrupted => None,
             PayloadError::Overflow => None,
             PayloadError::UnknownLength => None,
             #[cfg(feature = "http2")]
-            PayloadError::Http2Payload(err) => Some(err as &dyn std::error::Error),
-            PayloadError::Io(err) => Some(err as &dyn std::error::Error),
+            PayloadError::Http2Payload(err) => Some(err),
+            PayloadError::Io(err) => Some(err),
         }
     }
 }
@@ -323,15 +319,6 @@ impl From<io::Error> for PayloadError {
     }
 }
 
-impl From<BlockingError> for PayloadError {
-    fn from(_: BlockingError) -> Self {
-        PayloadError::Io(io::Error::new(
-            io::ErrorKind::Other,
-            "Operation is canceled",
-        ))
-    }
-}
-
 impl From<PayloadError> for Error {
     fn from(err: PayloadError) -> Self {
         Self::new_payload().with_cause(err)
@@ -386,7 +373,6 @@ pub enum DispatchError {
 impl StdError for DispatchError {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
         match self {
-            // TODO: error source extraction?
             DispatchError::Service(_res) => None,
             DispatchError::Body(err) => Some(&**err),
             DispatchError::Io(err) => Some(err),
diff --git a/actix-http/src/h1/dispatcher.rs b/actix-http/src/h1/dispatcher.rs
index fbc7e5b99..f029fb108 100644
--- a/actix-http/src/h1/dispatcher.rs
+++ b/actix-http/src/h1/dispatcher.rs
@@ -931,10 +931,16 @@ where
                 "dispatcher should not be in keep-alive phase if state is not none: {:?}",
                 this.state,
             );
-            debug_assert!(
-                this.write_buf.is_empty(),
-                "dispatcher should not be in keep-alive phase if write_buf is not empty",
-            );
+
+            // Assert removed by @robjtede on account of issue #2655. There are cases where an I/O
+            // flush can be pending after entering the keep-alive state causing the subsequent flush
+            // wake up to panic here. This appears to be a Linux-only problem. Leaving original code
+            // below for posterity because a simple and reliable test could not be found to trigger
+            // the behavior.
+            // debug_assert!(
+            //     this.write_buf.is_empty(),
+            //     "dispatcher should not be in keep-alive phase if write_buf is not empty",
+            // );
 
             // keep-alive timer has timed out
             if timer.as_mut().poll(cx).is_ready() {
diff --git a/actix-http/src/h2/dispatcher.rs b/actix-http/src/h2/dispatcher.rs
index d528bec96..ce1be537f 100644
--- a/actix-http/src/h2/dispatcher.rs
+++ b/actix-http/src/h2/dispatcher.rs
@@ -25,7 +25,9 @@ use pin_project_lite::pin_project;
 use crate::{
     body::{BodySize, BoxBody, MessageBody},
     config::ServiceConfig,
-    header::{HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING},
+    header::{
+        HeaderName, HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING, UPGRADE,
+    },
     service::HttpFlow,
     Extensions, OnConnectData, Payload, Request, Response, ResponseHead,
 };
@@ -306,13 +308,22 @@ fn prepare_response(
 
     // copy headers
     for (key, value) in head.headers.iter() {
-        match *key {
-            // TODO: consider skipping other headers according to:
-            //       https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.2
-            // omit HTTP/1.x only headers
-            CONNECTION | TRANSFER_ENCODING => continue,
-            CONTENT_LENGTH if skip_len => continue,
-            DATE => has_date = true,
+        match key {
+            // omit HTTP/1.x only headers according to:
+            // https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.2
+            &CONNECTION | &TRANSFER_ENCODING | &UPGRADE => continue,
+
+            &CONTENT_LENGTH if skip_len => continue,
+            &DATE => has_date = true,
+
+            // omit HTTP/1.x only headers according to:
+            // https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.2
+            hdr if hdr == HeaderName::from_static("keep-alive")
+                || hdr == HeaderName::from_static("proxy-connection") =>
+            {
+                continue
+            }
+
             _ => {}
         }
 
diff --git a/actix-http/src/ws/mask.rs b/actix-http/src/ws/mask.rs
index 20b4372a0..be72e5631 100644
--- a/actix-http/src/ws/mask.rs
+++ b/actix-http/src/ws/mask.rs
@@ -47,40 +47,6 @@ pub fn apply_mask_fast32(buf: &mut [u8], mask: [u8; 4]) {
 mod tests {
     use super::*;
 
-    // legacy test from old apply mask test. kept for now for back compat test.
-    // TODO: remove it and favor the other test.
-    #[test]
-    fn test_apply_mask_legacy() {
-        let mask = [0x6d, 0xb6, 0xb2, 0x80];
-
-        let unmasked = vec![
-            0xf3, 0x00, 0x01, 0x02, 0x03, 0x80, 0x81, 0x82, 0xff, 0xfe, 0x00, 0x17, 0x74, 0xf9,
-            0x12, 0x03,
-        ];
-
-        // Check masking with proper alignment.
-        {
-            let mut masked = unmasked.clone();
-            apply_mask_fallback(&mut masked, mask);
-
-            let mut masked_fast = unmasked.clone();
-            apply_mask(&mut masked_fast, mask);
-
-            assert_eq!(masked, masked_fast);
-        }
-
-        // Check masking without alignment.
-        {
-            let mut masked = unmasked.clone();
-            apply_mask_fallback(&mut masked[1..], mask);
-
-            let mut masked_fast = unmasked;
-            apply_mask(&mut masked_fast[1..], mask);
-
-            assert_eq!(masked, masked_fast);
-        }
-    }
-
     #[test]
     fn test_apply_mask() {
         let mask = [0x6d, 0xb6, 0xb2, 0x80];
diff --git a/actix-http/tests/test_server.rs b/actix-http/tests/test_server.rs
index 1b5de3425..e8d103c96 100644
--- a/actix-http/tests/test_server.rs
+++ b/actix-http/tests/test_server.rs
@@ -850,7 +850,8 @@ async fn not_modified_spec_h1() {
         Some(&header::HeaderValue::from_static("4")),
     );
     // server does not prevent payload from being sent but clients may choose not to read it
-    // TODO: this is probably a bug, especially since CL header can differ in length from the body
+    // TODO: this is probably a bug in the client, especially since CL header can differ in length
+    // from the body
     assert!(!srv.load_body(res).await.unwrap().is_empty());
 
     // TODO: add stream response tests
diff --git a/actix-multipart/CHANGES.md b/actix-multipart/CHANGES.md
index 71c8e958f..11ec8a64f 100644
--- a/actix-multipart/CHANGES.md
+++ b/actix-multipart/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 0.4.0 - 2022-02-25
+- No significant changes since `0.4.0-beta.13`.
+
+
 ## 0.4.0-beta.13 - 2022-01-31
 - No significant changes since `0.4.0-beta.12`.
 
diff --git a/actix-multipart/Cargo.toml b/actix-multipart/Cargo.toml
index 91cc96904..450a57fa9 100644
--- a/actix-multipart/Cargo.toml
+++ b/actix-multipart/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-multipart"
-version = "0.4.0-beta.13"
+version = "0.4.0"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Multipart form support for Actix Web"
 keywords = ["http", "web", "framework", "async", "futures"]
@@ -15,7 +15,7 @@ path = "src/lib.rs"
 
 [dependencies]
 actix-utils = "3.0.0"
-actix-web = { version = "4.0.0-rc.3", default-features = false }
+actix-web = { version = "4.0.0", default-features = false }
 
 bytes = "1"
 derive_more = "0.99.5"
@@ -28,7 +28,7 @@ twoway = "0.2"
 
 [dev-dependencies]
 actix-rt = "2.2"
-actix-http = "3.0.0-rc.3"
+actix-http = "3.0.0"
 futures-util = { version = "0.3.7", default-features = false, features = ["alloc"] }
 tokio = { version = "1.8.4", features = ["sync"] }
 tokio-stream = "0.1"
diff --git a/actix-multipart/README.md b/actix-multipart/README.md
index b517e8ded..59b9651f1 100644
--- a/actix-multipart/README.md
+++ b/actix-multipart/README.md
@@ -3,11 +3,11 @@
 > Multipart form support for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-multipart?label=latest)](https://crates.io/crates/actix-multipart)
-[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0-beta.13)](https://docs.rs/actix-multipart/0.4.0-beta.13)
+[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0)](https://docs.rs/actix-multipart/0.4.0)
 [![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-multipart.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0-beta.13/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0-beta.13)
+[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0)
 [![Download](https://img.shields.io/crates/d/actix-multipart.svg)](https://crates.io/crates/actix-multipart)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
diff --git a/actix-router/CHANGES.md b/actix-router/CHANGES.md
index ff9d8b4ab..8e0e4f41e 100644
--- a/actix-router/CHANGES.md
+++ b/actix-router/CHANGES.md
@@ -3,6 +3,77 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 0.5.0 - 2022-02-22
+### Added
+- Add `Path::as_str`. [#2590]
+- Add `ResourceDef::set_name`. [#373][net#373]
+- Add `RouterBuilder::push`. [#2612]
+- Implement `IntoPatterns` for `bytestring::ByteString`. [#372][net#372]
+- Introduce `ResourceDef::join`. [#380][net#380]
+- Introduce `ResourceDef::pattern_iter` to get an iterator over all patterns in a multi-pattern resource. [#373][net#373]
+- `Resource` is now implemented for `&mut Path<_>` and `RefMut<Path<_>>`. [#2568]
+- Support `build_resource_path` on multi-pattern resources. [#2356]
+- Support multi-pattern prefixes and joins. [#2356]
+
+### Changed
+- Change signature of `ResourceDef::capture_match_info_fn` to remove `user_data` parameter. [#2612]
+- Deprecate `Path::path`. [#2590]
+- Disallow prefix routes with tail segments. [#379][net#379]
+- Enforce path separators on dynamic prefixes. [#378][net#378]
+- Minimum supported Rust version (MSRV) is now 1.54.
+- Prefix segments now always end with with a segment delimiter or end-of-input. [#2355]
+- Prefix segments with trailing slashes define a trailing empty segment. [#2355]
+- `Quoter::requote` now returns `Option<Vec<u8>>`. [#2613]
+- Re-work `IntoPatterns` trait, adding a `Patterns` enum. [#372][net#372]
+- Rename `Path::{len => segment_count}` to be more descriptive of its purpose. [#370][net#370]
+- Rename `ResourceDef::{is_prefix_match => find_match}`. [#373][net#373]
+- Rename `ResourceDef::{match_path => capture_match_info}`. [#373][net#373]
+- Rename `ResourceDef::{match_path_checked => capture_match_info_fn}`. [#373][net#373]
+- Rename `ResourceDef::{resource_path => resource_path_from_iter}`. [#371][net#371]
+- Rename `ResourceDef::{resource_path_named => resource_path_from_map}`. [#371][net#371]
+- Rename `Router::{*_checked => *_fn}`. [#373][net#373]
+- Replace `Option<U>` with `U` in `Router` API. [#2612]
+- `Resource` trait now uses an associated type, `Path`, instead of a generic parameter. [#2568]
+- `ResourceDef::pattern` now returns the first pattern in multi-pattern resources. [#2356]
+- `ResourceDef::resource_path_from_iter` now takes an `IntoIterator`. [#373][net#373]
+- Return type of `ResourceDef::name` is now `Option<&str>`. [#373][net#373]
+- Return type of `ResourceDef::pattern` is now `Option<&str>`. [#373][net#373]
+
+### Fixed
+- Fix `ResourceDef`'s `PartialEq` implementation. [#373][net#373]
+- Fix segment interpolation leaving `Path` in unintended state after matching. [#368][net#368]
+- Improve malformed path error message. [#384][net#384]
+- `PathDeserializer` now decodes all percent encoded characters in dynamic segments. [#2566]
+- Relax bounds on `Router::recognize*` and `ResourceDef::capture_match_info`. [#2612]
+- Static patterns in multi-patterns are no longer interpreted as regex. [#366][net#366]
+
+### Removed
+- `ResourceDef::name_mut`. [#373][net#373]
+- Unused `ResourceInfo`. [#2612]
+
+[#2355]: https://github.com/actix/actix-web/pull/2355
+[#2356]: https://github.com/actix/actix-web/pull/2356
+[#2566]: https://github.com/actix/actix-net/pull/2566
+[#2568]: https://github.com/actix/actix-web/pull/2568
+[#2590]: https://github.com/actix/actix-web/pull/2590
+[#2612]: https://github.com/actix/actix-web/pull/2612
+[#2613]: https://github.com/actix/actix-web/pull/2613
+[net#366]: https://github.com/actix/actix-net/pull/366
+[net#368]: https://github.com/actix/actix-net/pull/368
+[net#368]: https://github.com/actix/actix-net/pull/368
+[net#370]: https://github.com/actix/actix-net/pull/370
+[net#371]: https://github.com/actix/actix-net/pull/371
+[net#372]: https://github.com/actix/actix-net/pull/372
+[net#373]: https://github.com/actix/actix-net/pull/373
+[net#378]: https://github.com/actix/actix-net/pull/378
+[net#379]: https://github.com/actix/actix-net/pull/379
+[net#380]: https://github.com/actix/actix-net/pull/380
+[net#384]: https://github.com/actix/actix-net/pull/384
+
+
+<details>
+<summary>0.5.0 Pre-Releases</summary>
+
 ## 0.5.0-rc.3 - 2022-01-31
 - Remove unused `ResourceInfo`. [#2612]
 - Add `RouterBuilder::push`. [#2612]
@@ -41,10 +112,10 @@
 
 
 ## 0.5.0-beta.2 - 2021-09-09
-- Introduce `ResourceDef::join`. [#380]
-- Disallow prefix routes with tail segments. [#379]
-- Enforce path separators on dynamic prefixes. [#378]
-- Improve malformed path error message. [#384]
+- Introduce `ResourceDef::join`. [#380][net#380]
+- Disallow prefix routes with tail segments. [#379][net#379]
+- Enforce path separators on dynamic prefixes. [#378][net#378]
+- Improve malformed path error message. [#384][net#384]
 - Prefix segments now always end with with a segment delimiter or end-of-input. [#2355]
 - Prefix segments with trailing slashes define a trailing empty segment. [#2355]
 - Support multi-pattern prefixes and joins. [#2356]
@@ -52,52 +123,54 @@
 - Support `build_resource_path` on multi-pattern resources. [#2356]
 - Minimum supported Rust version (MSRV) is now 1.51.
 
-[#378]: https://github.com/actix/actix-net/pull/378
-[#379]: https://github.com/actix/actix-net/pull/379
-[#380]: https://github.com/actix/actix-net/pull/380
-[#384]: https://github.com/actix/actix-net/pull/384
+[net#378]: https://github.com/actix/actix-net/pull/378
+[net#379]: https://github.com/actix/actix-net/pull/379
+[net#380]: https://github.com/actix/actix-net/pull/380
+[net#384]: https://github.com/actix/actix-net/pull/384
 [#2355]: https://github.com/actix/actix-web/pull/2355
 [#2356]: https://github.com/actix/actix-web/pull/2356
 
 
 ## 0.5.0-beta.1 - 2021-07-20
-- Fix a bug in multi-patterns where static patterns are interpreted as regex. [#366]
-- Introduce `ResourceDef::pattern_iter` to get an iterator over all patterns in a multi-pattern resource. [#373]
-- Fix segment interpolation leaving `Path` in unintended state after matching. [#368]
-- Fix `ResourceDef` `PartialEq` implementation. [#373]
-- Re-work `IntoPatterns` trait, adding a `Patterns` enum. [#372]
-- Implement `IntoPatterns` for `bytestring::ByteString`. [#372]
-- Rename `Path::{len => segment_count}` to be more descriptive of it's purpose. [#370]
-- Rename `ResourceDef::{resource_path => resource_path_from_iter}`. [#371]
-- `ResourceDef::resource_path_from_iter` now takes an `IntoIterator`. [#373]
-- Rename `ResourceDef::{resource_path_named => resource_path_from_map}`. [#371]
-- Rename `ResourceDef::{is_prefix_match => find_match}`. [#373]
-- Rename `ResourceDef::{match_path => capture_match_info}`. [#373]
-- Rename `ResourceDef::{match_path_checked => capture_match_info_fn}`. [#373]
-- Remove `ResourceDef::name_mut` and introduce `ResourceDef::set_name`. [#373]
-- Rename `Router::{*_checked => *_fn}`. [#373]
-- Return type of `ResourceDef::name` is now `Option<&str>`. [#373]
-- Return type of `ResourceDef::pattern` is now `Option<&str>`. [#373]
+- Fix a bug in multi-patterns where static patterns are interpreted as regex. [#366][net#366]
+- Introduce `ResourceDef::pattern_iter` to get an iterator over all patterns in a multi-pattern resource. [#373][net#373]
+- Fix segment interpolation leaving `Path` in unintended state after matching. [#368][net#368]
+- Fix `ResourceDef` `PartialEq` implementation. [#373][net#373]
+- Re-work `IntoPatterns` trait, adding a `Patterns` enum. [#372][net#372]
+- Implement `IntoPatterns` for `bytestring::ByteString`. [#372][net#372]
+- Rename `Path::{len => segment_count}` to be more descriptive of it's purpose. [#370][net#370]
+- Rename `ResourceDef::{resource_path => resource_path_from_iter}`. [#371][net#371]
+- `ResourceDef::resource_path_from_iter` now takes an `IntoIterator`. [#373][net#373]
+- Rename `ResourceDef::{resource_path_named => resource_path_from_map}`. [#371][net#371]
+- Rename `ResourceDef::{is_prefix_match => find_match}`. [#373][net#373]
+- Rename `ResourceDef::{match_path => capture_match_info}`. [#373][net#373]
+- Rename `ResourceDef::{match_path_checked => capture_match_info_fn}`. [#373][net#373]
+- Remove `ResourceDef::name_mut` and introduce `ResourceDef::set_name`. [#373][net#373]
+- Rename `Router::{*_checked => *_fn}`. [#373][net#373]
+- Return type of `ResourceDef::name` is now `Option<&str>`. [#373][net#373]
+- Return type of `ResourceDef::pattern` is now `Option<&str>`. [#373][net#373]
 
-[#368]: https://github.com/actix/actix-net/pull/368
-[#366]: https://github.com/actix/actix-net/pull/366
-[#368]: https://github.com/actix/actix-net/pull/368
-[#370]: https://github.com/actix/actix-net/pull/370
-[#371]: https://github.com/actix/actix-net/pull/371
-[#372]: https://github.com/actix/actix-net/pull/372
-[#373]: https://github.com/actix/actix-net/pull/373
+[net#368]: https://github.com/actix/actix-net/pull/368
+[net#366]: https://github.com/actix/actix-net/pull/366
+[net#368]: https://github.com/actix/actix-net/pull/368
+[net#370]: https://github.com/actix/actix-net/pull/370
+[net#371]: https://github.com/actix/actix-net/pull/371
+[net#372]: https://github.com/actix/actix-net/pull/372
+[net#373]: https://github.com/actix/actix-net/pull/373
+
+</details>
 
 
 ## 0.4.0 - 2021-06-06
-- When matching path parameters, `%25` is now kept in the percent-encoded form; no longer decoded to `%`. [#357]
-- Path tail patterns now match new lines (`\n`) in request URL. [#360]
-- Fixed a safety bug where `Path` could return a malformed string after percent decoding. [#359]
-- Methods `Path::{add, add_static}` now take `impl Into<Cow<'static, str>>`. [#345]
+- When matching path parameters, `%25` is now kept in the percent-encoded form; no longer decoded to `%`. [#357][net#357]
+- Path tail patterns now match new lines (`\n`) in request URL. [#360][net#360]
+- Fixed a safety bug where `Path` could return a malformed string after percent decoding. [#359][net#359]
+- Methods `Path::{add, add_static}` now take `impl Into<Cow<'static, str>>`. [#345][net#345]
 
-[#345]: https://github.com/actix/actix-net/pull/345
-[#357]: https://github.com/actix/actix-net/pull/357
-[#359]: https://github.com/actix/actix-net/pull/359
-[#360]: https://github.com/actix/actix-net/pull/360
+[net#345]: https://github.com/actix/actix-net/pull/345
+[net#357]: https://github.com/actix/actix-net/pull/357
+[net#359]: https://github.com/actix/actix-net/pull/359
+[net#360]: https://github.com/actix/actix-net/pull/360
 
 
 ## 0.3.0 - 2019-12-31
@@ -105,15 +178,15 @@
 
 
 ## 0.2.7 - 2021-02-06
-- Add `Router::recognize_checked` [#247]
+- Add `Router::recognize_checked` [#247][net#247]
 
-[#247]: https://github.com/actix/actix-net/pull/247
+[net#247]: https://github.com/actix/actix-net/pull/247
 
 
 ## 0.2.6 - 2021-01-09
-- Use `bytestring` version range compatible with Bytes v1.0. [#246]
+- Use `bytestring` version range compatible with Bytes v1.0. [#246][net#246]
 
-[#246]: https://github.com/actix/actix-net/pull/246
+[net#246]: https://github.com/actix/actix-net/pull/246
 
 
 ## 0.2.5 - 2020-09-20
diff --git a/actix-router/Cargo.toml b/actix-router/Cargo.toml
index 647a34479..502109114 100644
--- a/actix-router/Cargo.toml
+++ b/actix-router/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-router"
-version = "0.5.0-rc.3"
+version = "0.5.0"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "Ali MJ Al-Nasrawy <alimjalnasrawy@gmail.com>",
diff --git a/actix-test/Cargo.toml b/actix-test/Cargo.toml
index 21aeec1da..af4aff56a 100644
--- a/actix-test/Cargo.toml
+++ b/actix-test/Cargo.toml
@@ -29,12 +29,12 @@ openssl = ["tls-openssl", "actix-http/openssl", "awc/openssl"]
 
 [dependencies]
 actix-codec = "0.5"
-actix-http = "3.0.0-rc.3"
+actix-http = "3.0.0"
 actix-http-test = "3.0.0-beta.13"
 actix-rt = "2.1"
 actix-service = "2.0.0"
 actix-utils = "3.0.0"
-actix-web = { version = "4.0.0-rc.3", default-features = false, features = ["cookies"] }
+actix-web = { version = "4.0.0", default-features = false, features = ["cookies"] }
 awc = { version = "3.0.0-beta.21", default-features = false, features = ["cookies"] }
 
 futures-core = { version = "0.3.7", default-features = false, features = ["std"] }
diff --git a/actix-test/src/lib.rs b/actix-test/src/lib.rs
index d44bc7a45..5efd9758e 100644
--- a/actix-test/src/lib.rs
+++ b/actix-test/src/lib.rs
@@ -43,7 +43,7 @@ pub use actix_http_test::unused_addr;
 use actix_service::{map_config, IntoServiceFactory, ServiceFactory, ServiceFactoryExt as _};
 pub use actix_web::test::{
     call_and_read_body, call_and_read_body_json, call_service, init_service, ok_service,
-    read_body, read_body_json, simple_service, TestRequest,
+    read_body, read_body_json, status_service, TestRequest,
 };
 use actix_web::{
     body::MessageBody,
diff --git a/actix-web-actors/CHANGES.md b/actix-web-actors/CHANGES.md
index 124fe23b1..b4844bfa6 100644
--- a/actix-web-actors/CHANGES.md
+++ b/actix-web-actors/CHANGES.md
@@ -3,6 +3,16 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 4.1.0 - 2022-03-02
+- Add support for `actix` version `0.13`. [#2675]
+
+[#2675]: https://github.com/actix/actix-web/pull/2675
+
+
+## 4.0.0 - 2022-02-25
+- No significant changes since `4.0.0-beta.12`.
+
+
 ## 4.0.0-beta.12 - 2022-02-16
 - No significant changes since `4.0.0-beta.11`.
 
diff --git a/actix-web-actors/Cargo.toml b/actix-web-actors/Cargo.toml
index 121c86eb7..225326565 100644
--- a/actix-web-actors/Cargo.toml
+++ b/actix-web-actors/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web-actors"
-version = "4.0.0-beta.12"
+version = "4.1.0"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Actix actors support for Actix Web"
 keywords = ["actix", "http", "web", "framework", "async"]
@@ -14,16 +14,16 @@ name = "actix_web_actors"
 path = "src/lib.rs"
 
 [dependencies]
-actix = { version = "0.12.0", default-features = false }
+actix = { version = ">=0.12, <0.14", default-features = false }
 actix-codec = "0.5"
-actix-http = "3.0.0-rc.3"
-actix-web = { version = "4.0.0-rc.3", default-features = false }
+actix-http = "3"
+actix-web = { version = "4", default-features = false }
 
 bytes = "1"
 bytestring = "1"
 futures-core = { version = "0.3.7", default-features = false }
 pin-project-lite = "0.2"
-tokio = { version = "1.8.4", features = ["sync"] }
+tokio = { version = "1.13.1", features = ["sync"] }
 
 [dev-dependencies]
 actix-rt = "2.2"
diff --git a/actix-web-actors/README.md b/actix-web-actors/README.md
index 0964cb04e..357154a86 100644
--- a/actix-web-actors/README.md
+++ b/actix-web-actors/README.md
@@ -3,11 +3,11 @@
 > Actix actors support for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-web-actors?label=latest)](https://crates.io/crates/actix-web-actors)
-[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.0.0-beta.12)](https://docs.rs/actix-web-actors/4.0.0-beta.12)
+[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.1.0)](https://docs.rs/actix-web-actors/4.1.0)
 [![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
 ![License](https://img.shields.io/crates/l/actix-web-actors.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-actors/4.0.0-beta.12/status.svg)](https://deps.rs/crate/actix-web-actors/4.0.0-beta.12)
+[![dependency status](https://deps.rs/crate/actix-web-actors/4.1.0/status.svg)](https://deps.rs/crate/actix-web-actors/4.1.0)
 [![Download](https://img.shields.io/crates/d/actix-web-actors.svg)](https://crates.io/crates/actix-web-actors)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
diff --git a/actix-web-codegen/CHANGES.md b/actix-web-codegen/CHANGES.md
index 9483f1b35..8ee787c0a 100644
--- a/actix-web-codegen/CHANGES.md
+++ b/actix-web-codegen/CHANGES.md
@@ -3,6 +3,15 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 4.0.0 - 2022-02-24
+- Version aligned with `actix-web` and will remain in sync going forward.
+- No significant changes since `0.5.0`.
+
+
+## 0.5.0 - 2022-02-24
+- No significant changes since `0.5.0-rc.2`.
+
+
 ## 0.5.0-rc.2 - 2022-02-01
 - No significant changes since `0.5.0-rc.1`.
 
diff --git a/actix-web-codegen/Cargo.toml b/actix-web-codegen/Cargo.toml
index e3ff61509..0d8b86459 100644
--- a/actix-web-codegen/Cargo.toml
+++ b/actix-web-codegen/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web-codegen"
-version = "0.5.0-rc.2"
+version = "4.0.0"
 description = "Routing and runtime macros for Actix Web"
 homepage = "https://actix.rs"
 repository = "https://github.com/actix/actix-web.git"
@@ -15,7 +15,7 @@ edition = "2018"
 proc-macro = true
 
 [dependencies]
-actix-router = "0.5.0-rc.3"
+actix-router = "0.5.0"
 proc-macro2 = "1"
 quote = "1"
 syn = { version = "1", features = ["full", "parsing"] }
@@ -25,7 +25,7 @@ actix-macros = "0.2.3"
 actix-rt = "2.2"
 actix-test = "0.1.0-beta.13"
 actix-utils = "3.0.0"
-actix-web = "4.0.0-rc.3"
+actix-web = "4.0.0"
 
 futures-core = { version = "0.3.7", default-features = false, features = ["alloc"] }
 trybuild = "1"
diff --git a/actix-web-codegen/README.md b/actix-web-codegen/README.md
index f4e8344f3..439beadb4 100644
--- a/actix-web-codegen/README.md
+++ b/actix-web-codegen/README.md
@@ -3,11 +3,11 @@
 > Routing and runtime macros for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-web-codegen?label=latest)](https://crates.io/crates/actix-web-codegen)
-[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=0.5.0-rc.2)](https://docs.rs/actix-web-codegen/0.5.0-rc.2)
+[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=4.0.0)](https://docs.rs/actix-web-codegen/4.0.0)
 [![Version](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.54.0.html)
 ![License](https://img.shields.io/crates/l/actix-web-codegen.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-codegen/0.5.0-rc.2/status.svg)](https://deps.rs/crate/actix-web-codegen/0.5.0-rc.2)
+[![dependency status](https://deps.rs/crate/actix-web-codegen/4.0.0/status.svg)](https://deps.rs/crate/actix-web-codegen/4.0.0)
 [![Download](https://img.shields.io/crates/d/actix-web-codegen.svg)](https://crates.io/crates/actix-web-codegen)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
diff --git a/actix-web/CHANGES.md b/actix-web/CHANGES.md
index 3d1c0b9e2..8ee5c9837 100644
--- a/actix-web/CHANGES.md
+++ b/actix-web/CHANGES.md
@@ -1,4 +1,4 @@
-# Changes
+# Changelog
 
 ## Unreleased - 2021-xx-xx
 
@@ -8,6 +8,283 @@
 
 [#2631]: https://github.com/actix/actix-web/pull/2631
 
+## 4.0.1 - 2022-02-25
+### Fixed
+- Use stable version in readme example.
+
+
+## 4.0.0 - 2022-02-25
+### Dependencies
+- Updated `actix-*` to Tokio v1-based versions. [#1813]
+- Updated `actix-web-codegen` to `4.0.0`.
+- Updated `cookie` to `0.16`. [#2555]
+- Updated `language-tags` to `0.3`.
+- Updated `rand` to `0.8`.
+- Updated `rustls` to `0.20.0`. [#2414]
+- Updated `tokio` to `1`.
+
+### Added
+- Crate Features:
+  - `cookies`; enabled by default. [#2619]
+  - `compress-brotli`; enabled by default. [#2618]
+  - `compress-gzip`; enabled by default. [#2618]
+  - `compress-zstd`; enabled by default. [#2618]
+  - `macros`; enables routing and runtime macros, enabled by default. [#2619]
+- Types:
+  - `CustomizeResponder` for customizing response. [#2510]
+  - `dev::ServerHandle` re-export from `actix-server`. [#2442]
+  - `dev::ServiceFactory` re-export from `actix-service`. [#2325]
+  - `guard::GuardContext` for use with the `Guard` trait. [#2552]
+  - `http::header::AcceptEncoding` typed header. [#2482]
+  - `http::header::Range` typed header. [#2485]
+  - `http::KeepAlive` re-export from `actix-http`. [#2625]
+  - `middleware::Compat` that boxes middleware types like `Logger` and `Compress` to be used with constrained type bounds. [#1865]
+  - `web::Header` extractor for extracting typed HTTP headers in handlers. [#2094]
+- Methods:
+  - `dev::ServiceRequest::guard_ctx()` for obtaining a guard context. [#2552]
+  - `dev::ServiceRequest::parts_mut()`. [#2177]
+  - `dev::ServiceResponse::map_into_{left,right}_body()` and `HttpResponse::map_into_boxed_body()`. [#2468]
+  - `Either<web::Json<T>, web::Form<T>>::into_inner()` which returns the inner type for whichever variant was created. Also works for `Either<web::Form<T>, web::Json<T>>`. [#1894]
+  - `http::header::AcceptLanguage::{ranked, preference}()`. [#2480]
+  - `HttpResponse::add_removal_cookie()`. [#2586]
+  - `HttpResponse::map_into_{left,right}_body()` and `HttpResponse::map_into_boxed_body()`. [#2468]
+  - `HttpServer::worker_max_blocking_threads` for setting block thread pool. [#2200]
+  - `middleware::Logger::log_target()` to allow customize. [#2594]
+  - `Responder::customize()` trait method that wraps responder in `CustomizeResponder`. [#2510]
+  - `Route::service()` for using hand-written services as handlers. [#2262]
+  - `ServiceResponse::into_parts()`. [#2499]
+  - `TestServer::client_headers()` method. [#2097]
+  - `web::ServiceConfig::configure()` to allow easy nesting of configuration functions. [#1988]
+- Trait Implementations:
+  - Implement `Debug` for `DefaultHeaders`. [#2510]
+  - Implement `FromRequest` for `ConnectionInfo` and `PeerAddr`. [#2263]
+  - Implement `FromRequest` for `Method`. [#2263]
+  - Implement `FromRequest` for `Uri`. [#2263]
+  - Implement `Hash` for `http::header::Encoding`. [#2501]
+  - Implement `Responder` for `Vec<u8>`. [#2625]
+- Misc:
+  - `#[actix_web::test]` macro for setting up tests with a runtime. [#2409]
+  - Enable registering a vec of services of the same type to `App` [#1933]
+  - Add `services!` macro for helping register multiple services to `App`. [#1933]
+  - Option to allow `Json` extractor to work without a `Content-Type` header present. [#2362]
+  - Connection data set through the `HttpServer::on_connect` callback is now accessible only from the new `HttpRequest::conn_data()` and `ServiceRequest::conn_data()` methods. [#2491]
+
+### Changed
+- Functions:
+  - `guard::fn_guard` functions now receives a `&GuardContext`. [#2552]
+  - `guard::Not` is now generic over the type of guard it wraps. [#2552]
+  - `test::{call_service, read_response, read_response_json, send_request}()` now receive a `&Service`. [#1905]
+  - Some guard functions now return `impl Guard` and their concrete types are made private: `guard::Header` and all the method guards. [#2552]
+  - Rename `test::{default_service => status_service}()`. Old name is deprecated. [#2518]
+  - Rename `test::{read_response_json => call_and_read_body_json}()`. Old name is deprecated. [#2518]
+  - Rename `test::{read_response => call_and_read_body}()`. Old name is deprecated. [#2518]
+- Traits:
+  - `guard::Guard::check` now receives a `&GuardContext`. [#2552]
+  - `FromRequest::Config` associated type was removed. [#2233]
+  - `Responder` trait has been reworked and now `Response`/`HttpResponse` synchronously, making it simpler and more performant. [#1891]
+  - Rename `Factory` trait to `Handler`. [#1852]
+- Types:
+  - `App`'s `B` (body) type parameter been removed. As a result, `App`s can be returned from functions now. [#2493]
+  - `Compress` middleware's response type is now `EitherBody<Encoder<B>>`. [#2448]
+  - `error::BlockingError` is now a unit struct. It's now only triggered when blocking thread pool has shutdown. [#1957]
+  - `ErrorHandlerResponse`'s response variants now use `ServiceResponse<EitherBody<B>>`. [#2515]
+  - `ErrorHandlers` middleware's response types now use `ServiceResponse<EitherBody<B>>`. [#2515]
+  - `http::header::Encoding` now only represents `Content-Encoding` types. [#2501]
+  - `middleware::Condition` gained a broader middleware compatibility. [#2635]
+  - `Resource` no longer require service body type to be boxed. [#2526]
+  - `Scope` no longer require service body type to be boxed. [#2523]
+  - `web::Path`s inner field is now private. [#1894]
+  - `web::Payload`'s inner field is now private. [#2384]
+  - Error enums are now marked `#[non_exhaustive]`. [#2148]
+- Enum Variants:
+  - `Either` now uses `Left`/`Right` variants (instead of `A`/`B`) [#1894]
+  - Include size and limits in `JsonPayloadError::Overflow`. [#2162]
+- Methods:
+  - `App::data()` is deprecated; `App::app_data()` should be preferred. [#2271]
+  - `dev::JsonBody::new()` returns a default limit of 32kB to be consistent with `JsonConfig` and the default behaviour of the `web::Json<T>` extractor. [#2010]
+  - `dev::ServiceRequest::{into_parts, from_parts}()` can no longer fail. [#1893]
+  - `dev::ServiceRequest::from_request` can no longer fail. [#1893]
+  - `dev::ServiceResponse::error_response()` now uses body type of `BoxBody`. [#2201]
+  - `dev::ServiceResponse::map_body()` closure receives and returns `B` instead of `ResponseBody<B>`. [#2201]
+  - `http::header::ContentType::html()` now produces `text/html; charset=utf-8` instead of `text/html`. [#2423]
+  - `HttpRequest::url_for`'s constructed URLs no longer contain query or fragment. [#2430]
+  - `HttpResponseBuilder::json()` can now receive data by value and reference. [#1903]
+  - `HttpServer::{listen_rustls, bind_rustls}()` now honor the ALPN protocols in the configuration parameter. [#2226]
+  - `middleware::NormalizePath()` now will not try to normalize URIs with no valid path [#2246]
+  - `test::TestRequest::param()` now accepts more than just static strings. [#2172]
+  - `web::Data::into_inner()` and `Data::get_ref()` no longer require `T: Sized`. [#2403]
+  - Rename `HttpServer::{client_timeout => client_request_timeout}()`. [#2611]
+  - Rename `HttpServer::{client_shutdown => client_disconnect_timeout}()`. [#2611]
+  - Rename `http::header::Accept::{mime_precedence => ranked}()`. [#2480]
+  - Rename `http::header::Accept::{mime_preference => preference}()`. [#2480]
+  - Rename `middleware::DefaultHeaders::{content_type => add_content_type}()`. [#1875]
+  - Rename `dev::ConnectionInfo::{remote_addr => peer_addr}`, deprecating the old name. [#2554]
+- Trait Implementations:
+  - `HttpResponse` can now be used as a `Responder` with any body type. [#2567]
+- Misc:
+  - Maximum number of handler extractors has increased to 12. [#2582]
+  - The default `TrailingSlash` behavior is now `Trim`, in line with existing documentation. See migration guide for implications. [#1875]
+  - `Result` extractor wrapper can now convert error types. [#2581]
+  - Compress middleware will return `406 Not Acceptable` when no content encoding is acceptable to the client. [#2344]
+  - Adjusted default JSON payload limit to 2MB (from 32kb). [#2162]
+  - All error trait bounds in server service builders have changed from `Into<Error>` to `Into<Response<BoxBody>>`. [#2253]
+  - All error trait bounds in message body and stream impls changed from `Into<Error>` to `Into<Box<dyn std::error::Error>>`. [#2253]
+  - Improve spec compliance of `dev::ConnectionInfo` extractor. [#2282]
+  - Associated types in `FromRequest` implementation for `Option` and `Result` have changed. [#2581]
+  - Reduce the level from `error` to `debug` for the log line that is emitted when a `500 Internal Server Error` is built using `HttpResponse::from_error`. [#2201]
+  - Minimum supported Rust version (MSRV) is now 1.54.
+
+### Fixed
+- Auto-negotiation of content encoding is more fault-tolerant when using the `Compress` middleware. [#2501]
+- Scope and Resource middleware can access data items set on their own layer. [#2288]
+- Multiple calls to `App::data()` with the same type now keeps the latest call's data. [#1906]
+- Typed headers containing lists that require one or more items now enforce this minimum. [#2482]
+- `dev::ConnectionInfo::peer_addr` will no longer return the port number. [#2554]
+- `dev::ConnectionInfo::realip_remote_addr` will no longer return the port number if sourcing the IP from the peer's socket address. [#2554]
+- Accept wildcard `*` items in `AcceptLanguage`. [#2480]
+- Relax `Unpin` bound on `S` (stream) parameter of `HttpResponseBuilder::streaming`. [#2448]
+- Fix quality parse error in `http::header::AcceptEncoding` typed header. [#2344]
+- Double ampersand in `middleware::Logger` format is escaped correctly. [#2067]
+- Added the underlying parse error to `test::read_body_json`'s panic message. [#1812]
+
+### Security
+- `cookie` upgrade addresses [`RUSTSEC-2020-0071`].
+
+[`rustsec-2020-0071`]: https://rustsec.org/advisories/RUSTSEC-2020-0071.html
+
+### Removed
+- Crate Features:
+  - `compress` feature. [#2065]
+- Functions:
+  - `test::load_stream` and `test::load_body`; replace usage with `body::to_bytes`. [#2518]
+  - `test::start_with`; moved to new `actix-test` crate. [#2112]
+  - `test::start`; moved to new `actix-test` crate. [#2112]
+  - `test::unused_addr`; moved to new `actix-test` crate. [#2112]
+- Traits:
+  - `BodyEncoding`; signalling content encoding is now only done via the `Content-Encoding` header. [#2565]
+- Types:
+  - `dev::{BodySize, MessageBody, SizedStream}` re-exports; they are exposed through the `body` module. [#2468]
+  - `EitherExtractError` direct export. [#2510]
+  - `rt::{Arbiter, ArbiterHandle}` re-exports. [#2619]
+  - `test::TestServer`; moved to new `actix-test` crate. [#2112]
+  - `test::TestServerConfig`; moved to new `actix-test` crate. [#2112]
+  - `web::HttpRequest` re-export. [#2663]
+  - `web::HttpResponse` re-export. [#2663]
+- Methods:
+  - `AppService::set_service_data`; for custom HTTP service factories adding application data, use the layered data model by calling `ServiceRequest::add_data_container` when handling requests instead. [#1906]
+  - `dev::ConnectionInfo::get`. [#2487]
+  - `dev::ServiceResponse::checked_expr`. [#2401]
+  - `HttpRequestBuilder::del_cookie`. [#2591]
+  - `HttpResponse::take_body` and old `HttpResponse::into_body` method that casted body type. [#2201]
+  - `HttpResponseBuilder::json2()`. [#1903]
+  - `middleware::Compress::new`; restricting compression algorithm is done through feature flags. [#2501]
+  - `test::TestRequest::with_header()`; use `test::TestRequest::default().insert_header()`. [#1869]
+- Trait Implementations:
+  - Implementation of `From<either::Either>` for `Either` crate. [#2516]
+  - Implementation of `Future` for `HttpResponse`. [#2601]
+- Misc:
+  - The `client` module was removed; use the `awc` crate directly. [871ca5e4]
+  - `middleware::{normalize, err_handlers}` modules; all necessary middleware types are now exposed in the `middleware` module.
+
+[#1812]: https://github.com/actix/actix-web/pull/1812
+[#1813]: https://github.com/actix/actix-web/pull/1813
+[#1852]: https://github.com/actix/actix-web/pull/1852
+[#1865]: https://github.com/actix/actix-web/pull/1865
+[#1869]: https://github.com/actix/actix-web/pull/1869
+[#1875]: https://github.com/actix/actix-web/pull/1875
+[#1878]: https://github.com/actix/actix-web/pull/1878
+[#1891]: https://github.com/actix/actix-web/pull/1891
+[#1893]: https://github.com/actix/actix-web/pull/1893
+[#1894]: https://github.com/actix/actix-web/pull/1894
+[#1903]: https://github.com/actix/actix-web/pull/1903
+[#1905]: https://github.com/actix/actix-web/pull/1905
+[#1906]: https://github.com/actix/actix-web/pull/1906
+[#1933]: https://github.com/actix/actix-web/pull/1933
+[#1957]: https://github.com/actix/actix-web/pull/1957
+[#1957]: https://github.com/actix/actix-web/pull/1957
+[#1981]: https://github.com/actix/actix-web/pull/1981
+[#1988]: https://github.com/actix/actix-web/pull/1988
+[#2010]: https://github.com/actix/actix-web/pull/2010
+[#2065]: https://github.com/actix/actix-web/pull/2065
+[#2067]: https://github.com/actix/actix-web/pull/2067
+[#2093]: https://github.com/actix/actix-web/pull/2093
+[#2094]: https://github.com/actix/actix-web/pull/2094
+[#2097]: https://github.com/actix/actix-web/pull/2097
+[#2112]: https://github.com/actix/actix-web/pull/2112
+[#2148]: https://github.com/actix/actix-web/pull/2148
+[#2162]: https://github.com/actix/actix-web/pull/2162
+[#2172]: https://github.com/actix/actix-web/pull/2172
+[#2177]: https://github.com/actix/actix-web/pull/2177
+[#2200]: https://github.com/actix/actix-web/pull/2200
+[#2201]: https://github.com/actix/actix-web/pull/2201
+[#2201]: https://github.com/actix/actix-web/pull/2201
+[#2233]: https://github.com/actix/actix-web/pull/2233
+[#2246]: https://github.com/actix/actix-web/pull/2246
+[#2250]: https://github.com/actix/actix-web/pull/2250
+[#2253]: https://github.com/actix/actix-web/pull/2253
+[#2262]: https://github.com/actix/actix-web/pull/2262
+[#2263]: https://github.com/actix/actix-web/pull/2263
+[#2271]: https://github.com/actix/actix-web/pull/2271
+[#2282]: https://github.com/actix/actix-web/pull/2282
+[#2288]: https://github.com/actix/actix-web/pull/2288
+[#2325]: https://github.com/actix/actix-web/pull/2325
+[#2344]: https://github.com/actix/actix-web/pull/2344
+[#2362]: https://github.com/actix/actix-web/pull/2362
+[#2379]: https://github.com/actix/actix-web/pull/2379
+[#2384]: https://github.com/actix/actix-web/pull/2384
+[#2401]: https://github.com/actix/actix-web/pull/2401
+[#2403]: https://github.com/actix/actix-web/pull/2403
+[#2409]: https://github.com/actix/actix-web/pull/2409
+[#2414]: https://github.com/actix/actix-web/pull/2414
+[#2423]: https://github.com/actix/actix-web/pull/2423
+[#2430]: https://github.com/actix/actix-web/pull/2430
+[#2442]: https://github.com/actix/actix-web/pull/2442
+[#2446]: https://github.com/actix/actix-web/pull/2446
+[#2448]: https://github.com/actix/actix-web/pull/2448
+[#2468]: https://github.com/actix/actix-web/pull/2468
+[#2474]: https://github.com/actix/actix-web/pull/2474
+[#2480]: https://github.com/actix/actix-web/pull/2480
+[#2482]: https://github.com/actix/actix-web/pull/2482
+[#2484]: https://github.com/actix/actix-web/pull/2484
+[#2485]: https://github.com/actix/actix-web/pull/2485
+[#2487]: https://github.com/actix/actix-web/pull/2487
+[#2491]: https://github.com/actix/actix-web/pull/2491
+[#2492]: https://github.com/actix/actix-web/pull/2492
+[#2493]: https://github.com/actix/actix-web/pull/2493
+[#2499]: https://github.com/actix/actix-web/pull/2499
+[#2501]: https://github.com/actix/actix-web/pull/2501
+[#2510]: https://github.com/actix/actix-web/pull/2510
+[#2515]: https://github.com/actix/actix-web/pull/2515
+[#2516]: https://github.com/actix/actix-web/pull/2516
+[#2518]: https://github.com/actix/actix-web/pull/2518
+[#2523]: https://github.com/actix/actix-web/pull/2523
+[#2526]: https://github.com/actix/actix-web/pull/2526
+[#2552]: https://github.com/actix/actix-web/pull/2552
+[#2554]: https://github.com/actix/actix-web/pull/2554
+[#2555]: https://github.com/actix/actix-web/pull/2555
+[#2565]: https://github.com/actix/actix-web/pull/2565
+[#2567]: https://github.com/actix/actix-web/pull/2567
+[#2569]: https://github.com/actix/actix-web/pull/2569
+[#2581]: https://github.com/actix/actix-web/pull/2581
+[#2582]: https://github.com/actix/actix-web/pull/2582
+[#2584]: https://github.com/actix/actix-web/pull/2584
+[#2585]: https://github.com/actix/actix-web/pull/2585
+[#2586]: https://github.com/actix/actix-web/pull/2586
+[#2591]: https://github.com/actix/actix-web/pull/2591
+[#2594]: https://github.com/actix/actix-web/pull/2594
+[#2601]: https://github.com/actix/actix-web/pull/2601
+[#2611]: https://github.com/actix/actix-web/pull/2611
+[#2619]: https://github.com/actix/actix-web/pull/2619
+[#2625]: https://github.com/actix/actix-web/pull/2625
+[#2635]: https://github.com/actix/actix-web/pull/2635
+[#2659]: https://github.com/actix/actix-web/pull/2659
+[#2663]: https://github.com/actix/actix-web/pull/2663
+[871ca5e4]: https://github.com/actix/actix-web/commit/871ca5e4ae2bdc22d1ea02701c2992fa8d04aed7
+
+
+<details>
+<summary>4.0.0 Pre-Releases</summary>
+
 ## 4.0.0-rc.3 - 2022-02-08
 
 ### Changed
@@ -499,6 +776,8 @@
 [#1875]: https://github.com/actix/actix-web/pull/1875
 [#1878]: https://github.com/actix/actix-web/pull/1878
 
+</details>
+
 ## 3.3.3 - 2021-12-18
 
 ### Changed
diff --git a/actix-web/Cargo.toml b/actix-web/Cargo.toml
index 938412090..6e453026a 100644
--- a/actix-web/Cargo.toml
+++ b/actix-web/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web"
-version = "4.0.0-rc.3"
+version = "4.0.1"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "Rob Ede <robjtede@icloud.com>",
@@ -71,12 +71,13 @@ actix-service = "2"
 actix-utils = "3"
 actix-tls = { version = "3", default-features = false, optional = true }
 
-actix-http = { version = "3.0.0-rc.3", features = ["http2", "ws"] }
-actix-router = "0.5.0-rc.3"
-actix-web-codegen = { version = "0.5.0-rc.2", optional = true }
+actix-http = { version = "3.0.0", features = ["http2", "ws"] }
+actix-router = "0.5.0"
+actix-web-codegen = { version = "4.0.0", optional = true }
 
 ahash = "0.7"
 bytes = "1"
+bytestring = "1"
 cfg-if = "1"
 cookie = { version = "0.16", features = ["percent-encode"], optional = true }
 derive_more = "0.99.5"
@@ -99,7 +100,7 @@ time = { version = "0.3", default-features = false, features = ["formatting"] }
 url = "2.1"
 
 [dev-dependencies]
-actix-files = "0.6.0-beta.16"
+actix-files = "0.6.0"
 actix-test = { version = "0.1.0-beta.13", features = ["openssl", "rustls"] }
 awc = { version = "3.0.0-beta.21", features = ["openssl"] }
 
diff --git a/actix-web/MIGRATION-4.0.md b/actix-web/MIGRATION-4.0.md
index b5109e3f2..7192d0bc6 100644
--- a/actix-web/MIGRATION-4.0.md
+++ b/actix-web/MIGRATION-4.0.md
@@ -3,8 +3,7 @@
 This guide walks you through the process of migrating from v3.x.y to v4.x.y.  
 If you are migrating to v4.x.y from an older version of Actix Web (v2.x.y or earlier), check out the other historical migration notes in this folder.
 
-This document is not designed to be exhaustive - it focuses on the most significant changes coming in v4.  
-You can find an exhaustive changelog in [CHANGES.md](./CHANGES.md), complete of PR links. If you think that some of the changes that we omitted deserve to be called out in this document, please open an issue or submit a PR. 
+This document is not designed to be exhaustive—it focuses on the most significant changes in v4. You can find an exhaustive changelog in the changelogs for [`actix-web`](./CHANGES.md#400---2022-02-25) and [`actix-http`](../actix-http/CHANGES.md#300---2022-02-25), complete with PR links. If you think there are any changes that deserve to be called out in this document, please open an issue or pull request.
 
 Headings marked with :warning: are **breaking behavioral changes**. They will probably not surface as compile-time errors though automated tests _might_ detect their effects on your app.
 
@@ -30,7 +29,7 @@ Headings marked with :warning: are **breaking behavioral changes**. They will pr
 - [Server Must Be Polled :warning:](#server-must-be-polled-warning)
 - [Guards API](#guards-api)
 - [Returning `HttpResponse` synchronously](#returning-httpresponse-synchronously)
-- [`#[actix_web::main]` and `#[tokio::main]`](#actixwebmain-and-tokiomain)
+- [`#[actix_web::main]` and `#[tokio::main]`](#actix_webmain-and-tokiomain)
 - [`web::block`](#webblock)
 
 ## MSRV
@@ -39,8 +38,9 @@ The MSRV of Actix Web has been raised from 1.42 to 1.54.
 
 ## Tokio v1 Ecosystem
 
-Actix Web v4 is now underpinned by `tokio`'s v1 ecosystem.  
-`cargo` supports having multiple versions of the same crate within the same dependency tree, but `tokio` v1 does not interoperate transparently with its previous versions (v0.2, v0.1). Some of your dependencies might rely on `tokio`, either directly or indirectly - if they are using an older version of `tokio`, check if an update is available.  
+Actix Web v4 is now underpinned by `tokio`'s v1 ecosystem.
+
+`cargo` supports having multiple versions of the same crate within the same dependency tree, but `tokio` v1 does not interoperate transparently with its previous versions (v0.2, v0.1). Some of your dependencies might rely on `tokio`, either directly or indirectly—if they are using an older version of `tokio`, check if an update is available.  
 The following command can help you to identify these dependencies:
 
 ```sh
@@ -59,8 +59,8 @@ Lots of modules have been re-organized in this release. If a compile error refer
 
 ## `NormalizePath` Middleware :warning:
 
-The default `NormalizePath` behavior now strips trailing slashes by default.  
-This was the _documented_ behaviour in Actix Web v3, but the _actual_ behaviour differed - the discrepancy has now been fixed.  
+The default `NormalizePath` behavior now strips trailing slashes by default. This was the _documented_ behaviour in Actix Web v3, but the _actual_ behaviour differed. The discrepancy has now been resolved.
+
 As a consequence of this change, routes defined with trailing slashes will become inaccessible when using `NormalizePath::default()`. Calling `NormalizePath::default()` will log a warning. We suggest to use `new` or `trim`.
 
 ```diff
@@ -103,8 +103,7 @@ The `compress` feature flag has been split into more granular feature flags, one
 
 ## `web::Path`
 
-The inner field for `web::Path` is now private.  
-It was causing too many issues when used with inner tuple types due to its `Deref` implementation.
+The inner field for `web::Path` is now private. It was causing ambiguity when trying to use tuple indexing due to its `Deref` implementation.
 
 ```diff
 - async fn handler(web::Path((foo, bar)): web::Path<(String, String)>) {
@@ -112,13 +111,15 @@ It was causing too many issues when used with inner tuple types due to its `Dere
 +   let (foo, bar) = params.into_inner();
 ```
 
+An alternative [path param type with public field but no `Deref` impl is available in `actix-web-lab`](https://docs.rs/actix-web-lab/0.12.0/actix_web_lab/extract/struct.Path.html).
+
 ## Rustls Crate Upgrade
 
 Actix Web now depends on version 0.20 of `rustls`. As a result, the server config builder has changed. [See the updated example project.](https://github.com/actix/examples/tree/master/https-tls/rustls/)
 
 ## Removed `awc` Client Re-export
 
-Actix Web's sister crate `awc` is no longer re-exported through the `client` module. This allows `awc` to have its own release cadence - its breaking changes are no longer blocked by Actix Web's (more conservative) release schedule.
+Actix Web's sister crate `awc` is no longer re-exported through the `client` module. This allows `awc` to have its own release cadence—its breaking changes are no longer blocked by Actix Web's (more conservative) release schedule.
 
 ```diff
 - use actix_web::client::Client;
@@ -134,11 +135,11 @@ Actix Web's sister crate `awc` is no longer re-exported through the `client` mod
 + use use actix_test::start;
 ```
 
-`TestServer` previously lived in `actix_web::test`, but it depends on `awc` which is no longer part of Actix Web's public API (see above). 
+`TestServer` previously lived in `actix_web::test`, but it depends on `awc` which is no longer part of Actix Web's public API (see above).
 
 ## Header APIs
 
-Header related APIs have been standardized across all `actix-*` crates. The terminology now better matches the underlying `HeaderMap` naming conventions. 
+Header related APIs have been standardized across all `actix-*` crates. The terminology now better matches the underlying `HeaderMap` naming conventions.
 
 In short, "insert" always indicates that any existing headers with the same name are overridden, while "append" is used for adding with no removal (e.g. multi-valued headers).
 
@@ -155,7 +156,7 @@ For request and response builder APIs, the new methods provide a unified interfa
 + .insert_header(ContentType::json())
 ```
 
-We chose to deprecate most of the old methods instead of removing them immediately - the warning notes will guide you on how to update. 
+We chose to deprecate most of the old methods instead of removing them immediately—the warning notes will guide you on how to update.
 
 ## Response Body Types
 
@@ -178,24 +179,159 @@ We have boosted the quality and completeness of the documentation for all items
 
 ### `BoxBody`
 
-`BoxBody` is a new type-erased body type. It's used for all error response bodies.  
-Creating a boxed body is best done by calling [`.boxed()`](https://docs.rs/actix-web/4/actix_web/body/trait.MessageBody.html#method.boxed) on a `MessageBody` type.
+`BoxBody` is a new type-erased body type.
+
+It can be useful when writing handlers, responders, and middleware when you want to trade a (very) small amount of performance for a simpler type.
+
+Creating a boxed body is done most efficiently by calling [`.boxed()`](https://docs.rs/actix-web/4/actix_web/body/trait.MessageBody.html#method.boxed) on a `MessageBody` type.
 
 ### `EitherBody`
 
-`EitherBody` is a new "either" type that is particularly useful in middlewares that can bail early, returning their own response plus body type.
+`EitherBody` is a new "either" type that implements `MessageBody`
+
+It is particularly useful in middleware that can bail early, returning their own response plus body type. By default the "right" variant is `BoxBody` (i.e., `EitherBody<B>` === `EitherBody<B, BoxBody>`) but it can be anything that implements `MessageBody`.
+
+For example, it will be common among middleware which value performance of the hot path to use:
+
+```rust
+type Response = Result<ServiceResponse<EitherBody<B>>, Error>
+```
+
+This can be read (ignoring the `Result`) as "resolves with a `ServiceResponse` that is either the inner service's `B` body type or a boxed body type from elsewhere, likely constructed within the middleware itself". Of course, if your middleware contains only simple string other/error responses, it's possible to use them without boxes at the cost of a less simple implementation:
+
+```rust
+type Response = Result<ServiceResponse<EitherBody<B, String>>, Error>
+```
 
 ### Error Handlers
 
-TODO In particular, folks seem to be struggling with the `ErrorHandlers` middleware because of this change and the obscured nature of `EitherBody` within its types.
+`ErrorHandlers` is a commonly used middleware that has changed in design slightly due to the other body type changes.
+
+In particular, an implicit `EitherBody` is used in the `ErrorHandlerResponse<B>` type. An `ErrorHandlerResponse<B>` now expects a `ServiceResponse<EitherBody<B>>` to be returned within response variants. The following is a migration for an error handler that **only modifies** the response argument (left body).
+
+```diff
+  fn add_error_header<B>(mut res: ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>, Error> {
+      res.response_mut().headers_mut().insert(
+          header::CONTENT_TYPE,
+          header::HeaderValue::from_static("Error"),
+      );
+-     Ok(ErrorHandlerResponse::Response(res))
++     Ok(ErrorHandlerResponse::Response(res.map_into_left_body()))
+  }
+```
+
+The following is a migration for an error handler that creates a new response instead (right body).
+
+```diff
+  fn error_handler<B>(res: ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>, Error> {
+-     let req = res.request().clone();
++     let (req, _res) = res.into_parts();
+
+      let res = actix_files::NamedFile::open("./templates/404.html")?
+          .set_status_code(StatusCode::NOT_FOUND)
+-         .into_response(&req)?
+-         .into_body();
++         .into_response(&req);
+
+-     let res = ServiceResponse::new(req, res);
++     let res = ServiceResponse::new(req, res).map_into_right_body();
+      Ok(ErrorHandlerResponse::Response(res))
+  }
+```
 
 ## Middleware Trait APIs
 
-This section builds upon guidance from the [response body types](#response-body-types) section.
+The underlying traits that are used for creating middleware, `Service`, `ServiceFactory`, and `Transform`, have changed in design.
 
-TODO
+- The associated `Request` type has moved to the type parameter position in order to allow multiple request implementations in other areas of the service stack.
+- The `self` arguments in `Service` have changed from exclusive (mutable) borrows to shared (immutable) borrows. Since most service layers, such as middleware, do not host mutable state, it reduces the runtime overhead in places where a `RefCell` used to be required for wrapping an inner service.
+- We've also introduced some macros that reduce boilerplate when implementing `poll_ready`.
+- Further to the guidance on [response body types](#response-body-types), any use of the old methods on `ServiceResponse` designed to match up body types (e.g., the old `into_body` method), should be replaced with an explicit response body type utilizing `EitherBody<B>`.
 
-TODO: Also write the Middleware author's guide.
+A typical migration would look like this:
+
+```diff
+  use std::{
+-     cell::RefCell,
+      future::Future,
+      pin::Pin,
+      rc::Rc,
+-     task::{Context, Poll},
+  };
+
+  use actix_web::{
+      dev::{Service, ServiceRequest, ServiceResponse, Transform},
+      Error,
+  };
+  use futures_util::future::{ok, LocalBoxFuture, Ready};
+
+  pub struct SayHi;
+
+- impl<S, B> Transform<S> for SayHi
++ impl<S, B> Transform<S, ServiceRequest> for SayHi
+  where
+-     S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
++     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+      S::Future: 'static,
+      B: 'static,
+  {
+-     type Request = ServiceRequest;
+      type Response = ServiceResponse<B>;
+      type Error = Error;
+      type InitError = ();
+      type Transform = SayHiMiddleware<S>;
+      type Future = Ready<Result<Self::Transform, Self::InitError>>;
+
+      fn new_transform(&self, service: S) -> Self::Future {
+          ok(SayHiMiddleware {
+-             service: Rc::new(RefCell::new(service)),
++             service: Rc::new(service),
+          })
+      }
+  }
+
+  pub struct SayHiMiddleware<S> {
+-     service: Rc<RefCell<S>>,
++     service: Rc<S>,
+  }
+
+- impl<S, B> Service for SayHiMiddleware<S>
++ impl<S, B> Service<ServiceRequest> for SayHiMiddleware<S>
+  where
+-     S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
++     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+      S::Future: 'static,
+      B: 'static,
+  {
+-     type Request = ServiceRequest;
+      type Response = ServiceResponse<B>;
+      type Error = Error;
+      type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+-     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+-         self.service.poll_ready(cx)
+-     }
++     actix_web::dev::forward_ready!(service);
+
+-     fn call(&mut self, req: ServiceRequest) -> Self::Future {
++     fn call(&self, req: ServiceRequest) -> Self::Future {
+          println!("Hi from start. You requested: {}", req.path());
+
+          let fut = self.service.call(req);
+
+          Box::pin(async move {
+              let res = fut.await?;
+
+              println!("Hi from response");
+              Ok(res)
+          })
+      }
+  }
+```
+
+This new design is forward-looking and should ease transition to traits that support the upcoming Generic Associated Type (GAT) feature in Rust while also trimming down the boilerplate required to implement middleware.
+
+We understand that creating middleware is still a pain point for Actix Web and we hope to provide [an even more ergonomic solution](https://docs.rs/actix-web-lab/0.11.0/actix_web_lab/middleware/fn.from_fn.html) in a v4.x release.
 
 ## `Responder` Trait
 
@@ -251,7 +387,7 @@ You may need to review the [guidance on shared mutable state](https://docs.rs/ac
 Improvements to module management and re-exports have resulted in not needing direct dependencies on these underlying crates for the vast majority of cases. In particular:
 
 - all traits necessary for creating middlewares are now re-exported through the `dev` modules;
-- `#[actix_web::test]` now exists for async test definitions. 
+- `#[actix_web::test]` now exists for async test definitions.
 
 Relying on these re-exports will ease the transition to future versions of Actix Web.
 
diff --git a/actix-web/README.md b/actix-web/README.md
index e66224524..d0abb3aae 100644
--- a/actix-web/README.md
+++ b/actix-web/README.md
@@ -6,10 +6,10 @@
   <p>
 
 [![crates.io](https://img.shields.io/crates/v/actix-web?label=latest)](https://crates.io/crates/actix-web)
-[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.0-rc.3)](https://docs.rs/actix-web/4.0.0-rc.3)
+[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.1)](https://docs.rs/actix-web/4.0.1)
 ![MSRV](https://img.shields.io/badge/rustc-1.54+-ab6000.svg)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-web.svg)
-[![Dependency Status](https://deps.rs/crate/actix-web/4.0.0-rc.3/status.svg)](https://deps.rs/crate/actix-web/4.0.0-rc.3)
+[![Dependency Status](https://deps.rs/crate/actix-web/4.0.1/status.svg)](https://deps.rs/crate/actix-web/4.0.1)
 <br />
 [![CI](https://github.com/actix/actix-web/actions/workflows/ci.yml/badge.svg)](https://github.com/actix/actix-web/actions/workflows/ci.yml)
 [![codecov](https://codecov.io/gh/actix/actix-web/branch/master/graph/badge.svg)](https://codecov.io/gh/actix/actix-web)
@@ -48,7 +48,7 @@ Dependencies:
 
 ```toml
 [dependencies]
-actix-web = "4.0.0-rc.1"
+actix-web = "4"
 ```
 
 Code:
diff --git a/actix-web/src/app.rs b/actix-web/src/app.rs
index be3526393..d2df72714 100644
--- a/actix-web/src/app.rs
+++ b/actix-web/src/app.rs
@@ -290,12 +290,10 @@ where
     ///     Ok(HttpResponse::Ok().into())
     /// }
     ///
-    /// fn main() {
-    ///     let app = App::new()
-    ///         .service(web::resource("/index.html").route(
-    ///             web::get().to(index)))
-    ///         .external_resource("youtube", "https://youtube.com/watch/{video_id}");
-    /// }
+    /// let app = App::new()
+    ///     .service(web::resource("/index.html").route(
+    ///         web::get().to(index)))
+    ///     .external_resource("youtube", "https://youtube.com/watch/{video_id}");
     /// ```
     pub fn external_resource<N, U>(mut self, name: N, url: U) -> Self
     where
diff --git a/actix-web/src/dev.rs b/actix-web/src/dev.rs
index def545ec7..5c7adfdaf 100644
--- a/actix-web/src/dev.rs
+++ b/actix-web/src/dev.rs
@@ -2,6 +2,10 @@
 //!
 //! Most users will not have to interact with the types in this module, but it is useful for those
 //! writing extractors, middleware, libraries, or interacting with the service API directly.
+//!
+//! # Request Extractors
+//! - [`ConnectionInfo`]: Connection information
+//! - [`PeerAddr`]: Connection information
 
 pub use actix_http::{Extensions, Payload, RequestHead, Response, ResponseHead};
 pub use actix_router::{Path, ResourceDef, ResourcePath, Url};
diff --git a/actix-web/src/error/error.rs b/actix-web/src/error/error.rs
index 8450bed35..3d3978dde 100644
--- a/actix-web/src/error/error.rs
+++ b/actix-web/src/error/error.rs
@@ -47,7 +47,6 @@ impl fmt::Debug for Error {
 
 impl StdError for Error {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        // TODO: populate if replacement for Box<dyn Error> is found
         None
     }
 }
diff --git a/actix-web/src/error/mod.rs b/actix-web/src/error/mod.rs
index 64df9f553..6095cd5d2 100644
--- a/actix-web/src/error/mod.rs
+++ b/actix-web/src/error/mod.rs
@@ -6,7 +6,7 @@
 //
 // See <https://github.com/rust-lang/rust/issues/83375>
 pub use actix_http::error::{
-    BlockingError, ContentTypeError, DispatchError, HttpError, ParseError, PayloadError,
+    ContentTypeError, DispatchError, HttpError, ParseError, PayloadError,
 };
 
 use derive_more::{Display, Error, From};
@@ -33,6 +33,14 @@ pub(crate) use macros::{downcast_dyn, downcast_get_type_id};
 /// This type alias is generally used to avoid writing out `actix_http::Error` directly.
 pub type Result<T, E = Error> = std::result::Result<T, E>;
 
+/// An error representing a problem running a blocking task on a thread pool.
+#[derive(Debug, Display, Error)]
+#[display(fmt = "Blocking thread pool is shut down unexpectedly")]
+#[non_exhaustive]
+pub struct BlockingError;
+
+impl ResponseError for crate::error::BlockingError {}
+
 /// Errors which can occur when attempting to generate resource uri.
 #[derive(Debug, PartialEq, Display, Error, From)]
 #[non_exhaustive]
diff --git a/actix-web/src/error/response_error.rs b/actix-web/src/error/response_error.rs
index e0b4af44c..0b8a82ce8 100644
--- a/actix-web/src/error/response_error.rs
+++ b/actix-web/src/error/response_error.rs
@@ -6,20 +6,22 @@ use std::{
     io::{self, Write as _},
 };
 
-use actix_http::{
-    body::BoxBody,
-    header::{self, TryIntoHeaderValue},
-    Response, StatusCode,
-};
+use actix_http::Response;
 use bytes::BytesMut;
 
 use crate::{
+    body::BoxBody,
     error::{downcast_dyn, downcast_get_type_id},
-    helpers, HttpResponse,
+    helpers,
+    http::{
+        header::{self, TryIntoHeaderValue},
+        StatusCode,
+    },
+    HttpResponse,
 };
 
 /// Errors that can generate responses.
-// TODO: add std::error::Error bound when replacement for Box<dyn Error> is found
+// TODO: flesh out documentation
 pub trait ResponseError: fmt::Debug + fmt::Display {
     /// Returns appropriate status code for error.
     ///
@@ -73,7 +75,6 @@ impl ResponseError for std::str::Utf8Error {
 
 impl ResponseError for std::io::Error {
     fn status_code(&self) -> StatusCode {
-        // TODO: decide if these errors should consider not found or permission errors
         match self.kind() {
             io::ErrorKind::NotFound => StatusCode::NOT_FOUND,
             io::ErrorKind::PermissionDenied => StatusCode::FORBIDDEN,
@@ -86,7 +87,6 @@ impl ResponseError for actix_http::error::HttpError {}
 
 impl ResponseError for actix_http::Error {
     fn status_code(&self) -> StatusCode {
-        // TODO: map error kinds to status code better
         StatusCode::INTERNAL_SERVER_ERROR
     }
 
@@ -107,8 +107,6 @@ impl ResponseError for actix_http::error::ParseError {
     }
 }
 
-impl ResponseError for actix_http::error::BlockingError {}
-
 impl ResponseError for actix_http::error::PayloadError {
     fn status_code(&self) -> StatusCode {
         match *self {
diff --git a/actix-web/src/extract.rs b/actix-web/src/extract.rs
index f16c29ca5..a8b3d4565 100644
--- a/actix-web/src/extract.rs
+++ b/actix-web/src/extract.rs
@@ -118,12 +118,10 @@ pub trait FromRequest: Sized {
 ///     }
 /// }
 ///
-/// fn main() {
-///     let app = App::new().service(
-///         web::resource("/users/:first").route(
-///             web::post().to(index))
-///     );
-/// }
+/// let app = App::new().service(
+///     web::resource("/users/:first").route(
+///         web::post().to(index))
+/// );
 /// ```
 impl<T> FromRequest for Option<T>
 where
@@ -205,11 +203,9 @@ where
 ///     }
 /// }
 ///
-/// fn main() {
-///     let app = App::new().service(
-///         web::resource("/users/:first").route(web::post().to(index))
-///     );
-/// }
+/// let app = App::new().service(
+///     web::resource("/users/:first").route(web::post().to(index))
+/// );
 /// ```
 impl<T, E> FromRequest for Result<T, E>
 where
diff --git a/actix-web/src/http/mod.rs b/actix-web/src/http/mod.rs
index 91c0ca377..2866e1a2c 100644
--- a/actix-web/src/http/mod.rs
+++ b/actix-web/src/http/mod.rs
@@ -2,5 +2,4 @@
 
 pub mod header;
 
-// TODO: figure out how best to expose http::Error vs actix_http::Error
 pub use actix_http::{uri, ConnectionType, Error, KeepAlive, Method, StatusCode, Uri, Version};
diff --git a/actix-web/src/info.rs b/actix-web/src/info.rs
index ce1ef97c6..77b98110e 100644
--- a/actix-web/src/info.rs
+++ b/actix-web/src/info.rs
@@ -159,7 +159,7 @@ impl ConnectionInfo {
     pub fn realip_remote_addr(&self) -> Option<&str> {
         self.realip_remote_addr
             .as_deref()
-            .or_else(|| self.peer_addr.as_deref())
+            .or(self.peer_addr.as_deref())
     }
 
     /// Returns serialized IP address of the peer connection.
diff --git a/actix-web/src/middleware/err_handlers.rs b/actix-web/src/middleware/err_handlers.rs
index bde054330..f74220cd2 100644
--- a/actix-web/src/middleware/err_handlers.rs
+++ b/actix-web/src/middleware/err_handlers.rs
@@ -185,6 +185,7 @@ mod tests {
 
     use super::*;
     use crate::{
+        body,
         http::{
             header::{HeaderValue, CONTENT_TYPE},
             StatusCode,
@@ -203,7 +204,7 @@ mod tests {
             Ok(ErrorHandlerResponse::Response(res.map_into_left_body()))
         }
 
-        let srv = test::simple_service(StatusCode::INTERNAL_SERVER_ERROR);
+        let srv = test::status_service(StatusCode::INTERNAL_SERVER_ERROR);
 
         let mw = ErrorHandlers::new()
             .handler(StatusCode::INTERNAL_SERVER_ERROR, error_handler)
@@ -230,7 +231,7 @@ mod tests {
             ))
         }
 
-        let srv = test::simple_service(StatusCode::INTERNAL_SERVER_ERROR);
+        let srv = test::status_service(StatusCode::INTERNAL_SERVER_ERROR);
 
         let mw = ErrorHandlers::new()
             .handler(StatusCode::INTERNAL_SERVER_ERROR, error_handler)
@@ -245,9 +246,7 @@ mod tests {
     #[actix_rt::test]
     async fn changes_body_type() {
         #[allow(clippy::unnecessary_wraps)]
-        fn error_handler<B: 'static>(
-            res: ServiceResponse<B>,
-        ) -> Result<ErrorHandlerResponse<B>> {
+        fn error_handler<B>(res: ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>> {
             let (req, res) = res.into_parts();
             let res = res.set_body(Bytes::from("sorry, that's no bueno"));
 
@@ -258,7 +257,7 @@ mod tests {
             Ok(ErrorHandlerResponse::Response(res))
         }
 
-        let srv = test::simple_service(StatusCode::INTERNAL_SERVER_ERROR);
+        let srv = test::status_service(StatusCode::INTERNAL_SERVER_ERROR);
 
         let mw = ErrorHandlers::new()
             .handler(StatusCode::INTERNAL_SERVER_ERROR, error_handler)
@@ -270,5 +269,33 @@ mod tests {
         assert_eq!(test::read_body(res).await, "sorry, that's no bueno");
     }
 
-    // TODO: test where error is thrown
+    #[actix_rt::test]
+    async fn error_thrown() {
+        #[allow(clippy::unnecessary_wraps)]
+        fn error_handler<B>(_res: ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>> {
+            Err(crate::error::ErrorInternalServerError(
+                "error in error handler",
+            ))
+        }
+
+        let srv = test::status_service(StatusCode::BAD_REQUEST);
+
+        let mw = ErrorHandlers::new()
+            .handler(StatusCode::BAD_REQUEST, error_handler)
+            .new_transform(srv.into_service())
+            .await
+            .unwrap();
+
+        let err = mw
+            .call(TestRequest::default().to_srv_request())
+            .await
+            .unwrap_err();
+        let res = err.error_response();
+
+        assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);
+        assert_eq!(
+            body::to_bytes(res.into_body()).await.unwrap(),
+            "error in error handler"
+        );
+    }
 }
diff --git a/actix-web/src/request.rs b/actix-web/src/request.rs
index f04e551d4..5545cf982 100644
--- a/actix-web/src/request.rs
+++ b/actix-web/src/request.rs
@@ -407,12 +407,10 @@ impl Drop for HttpRequest {
 ///    format!("Got thing: {:?}", req)
 /// }
 ///
-/// fn main() {
-///     let app = App::new().service(
-///         web::resource("/users/{first}").route(
-///             web::get().to(index))
-///     );
-/// }
+/// let app = App::new().service(
+///     web::resource("/users/{first}").route(
+///         web::get().to(index))
+/// );
 /// ```
 impl FromRequest for HttpRequest {
     type Error = Error;
diff --git a/actix-web/src/resource.rs b/actix-web/src/resource.rs
index 6a01a0496..c5c6701e6 100644
--- a/actix-web/src/resource.rs
+++ b/actix-web/src/resource.rs
@@ -93,19 +93,17 @@ where
     ///     "Welcome!"
     /// }
     ///
-    /// fn main() {
-    ///     let app = App::new()
-    ///         .service(
-    ///             web::resource("/app")
-    ///                 .guard(guard::Header("content-type", "text/plain"))
-    ///                 .route(web::get().to(index))
-    ///         )
-    ///         .service(
-    ///             web::resource("/app")
-    ///                 .guard(guard::Header("content-type", "text/json"))
-    ///                 .route(web::get().to(|| HttpResponse::MethodNotAllowed()))
-    ///         );
-    /// }
+    /// let app = App::new()
+    ///     .service(
+    ///         web::resource("/app")
+    ///             .guard(guard::Header("content-type", "text/plain"))
+    ///             .route(web::get().to(index))
+    ///     )
+    ///     .service(
+    ///         web::resource("/app")
+    ///             .guard(guard::Header("content-type", "text/json"))
+    ///             .route(web::get().to(|| HttpResponse::MethodNotAllowed()))
+    ///     );
     /// ```
     pub fn guard<G: Guard + 'static>(mut self, guard: G) -> Self {
         self.guards.push(Box::new(guard));
@@ -137,14 +135,13 @@ where
     /// ```
     /// use actix_web::{web, guard, App};
     ///
-    /// fn main() {
-    ///     let app = App::new().service(
-    ///         web::resource("/container/")
-    ///              .route(web::get().to(get_handler))
-    ///              .route(web::post().to(post_handler))
-    ///              .route(web::delete().to(delete_handler))
-    ///     );
-    /// }
+    /// let app = App::new().service(
+    ///     web::resource("/container/")
+    ///          .route(web::get().to(get_handler))
+    ///          .route(web::post().to(post_handler))
+    ///          .route(web::delete().to(delete_handler))
+    /// );
+    ///
     /// # async fn get_handler() -> impl actix_web::Responder { actix_web::HttpResponse::Ok() }
     /// # async fn post_handler() -> impl actix_web::Responder { actix_web::HttpResponse::Ok() }
     /// # async fn delete_handler() -> impl actix_web::Responder { actix_web::HttpResponse::Ok() }
diff --git a/actix-web/src/response/responder.rs b/actix-web/src/response/responder.rs
index c88faec89..da8091981 100644
--- a/actix-web/src/response/responder.rs
+++ b/actix-web/src/response/responder.rs
@@ -7,14 +7,35 @@ use actix_http::{
 };
 use bytes::{Bytes, BytesMut};
 
-use crate::{Error, HttpRequest, HttpResponse};
-
 use super::CustomizeResponder;
+use crate::{Error, HttpRequest, HttpResponse};
 
 /// Trait implemented by types that can be converted to an HTTP response.
 ///
-/// Any types that implement this trait can be used in the return type of a handler.
-// # TODO: more about implementation notes and foreign impls
+/// Any types that implement this trait can be used in the return type of a handler. Since handlers
+/// will only have one return type, it is idiomatic to use opaque return types `-> impl Responder`.
+///
+/// # Implementations
+/// It is often not required to implement `Responder` for your own types due to a broad base of
+/// built-in implementations:
+/// - `HttpResponse` and `HttpResponseBuilder`
+/// - `Option<R>` where `R: Responder`
+/// - `Result<R, E>` where `R: Responder` and [`E: ResponseError`](crate::ResponseError)
+/// - `(R, StatusCode) where `R: Responder`
+/// - `&'static str`, `String`, `&'_ String`, `Cow<'_, str>`, [`ByteString`](bytestring::ByteString)
+/// - `&'static [u8]`, `Vec<u8>`, `Bytes`, `BytesMut`
+/// - [`Json<T>`](crate::web::Json) and [`Form<T>`](crate::web::Form) where `T: Serialize`
+/// - [`Either<L, R>`](crate::web::Either) where `L: Serialize` and `R: Serialize`
+/// - [`CustomizeResponder<R>`]
+/// - [`actix_files::NamedFile`](https://docs.rs/actix-files/latest/actix_files/struct.NamedFile.html)
+/// - [Experimental responders from `actix-web-lab`](https://docs.rs/actix-web-lab/latest/actix_web_lab/respond/index.html)
+/// - Third party integrations may also have implemented `Responder` where appropriate. For example,
+///   HTML templating engines.
+///
+/// # Customizing Responder Output
+/// Calling [`.customize()`](Responder::customize) on any responder type will wrap it in a
+/// [`CustomizeResponder`] capable of overriding various parts of the response such as the status
+/// code and header map.
 pub trait Responder {
     type Body: MessageBody + 'static;
 
@@ -23,7 +44,7 @@ pub trait Responder {
 
     /// Wraps responder to allow alteration of its response.
     ///
-    /// See [`CustomizeResponder`] docs for its capabilities.
+    /// See [`CustomizeResponder`] docs for more details on its capabilities.
     ///
     /// # Examples
     /// ```
@@ -84,11 +105,8 @@ impl Responder for actix_http::ResponseBuilder {
     }
 }
 
-impl<T> Responder for Option<T>
-where
-    T: Responder,
-{
-    type Body = EitherBody<T::Body>;
+impl<R: Responder> Responder for Option<R> {
+    type Body = EitherBody<R::Body>;
 
     fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
         match self {
@@ -98,12 +116,12 @@ where
     }
 }
 
-impl<T, E> Responder for Result<T, E>
+impl<R, E> Responder for Result<R, E>
 where
-    T: Responder,
+    R: Responder,
     E: Into<Error>,
 {
-    type Body = EitherBody<T::Body>;
+    type Body = EitherBody<R::Body>;
 
     fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
         match self {
@@ -113,8 +131,8 @@ where
     }
 }
 
-impl<T: Responder> Responder for (T, StatusCode) {
-    type Body = T::Body;
+impl<R: Responder> Responder for (R, StatusCode) {
+    type Body = R::Body;
 
     fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
         let mut res = self.0.respond_to(req);
@@ -147,6 +165,7 @@ impl_responder_by_forward_into_base_response!(BytesMut);
 
 impl_responder_by_forward_into_base_response!(&'static str);
 impl_responder_by_forward_into_base_response!(String);
+impl_responder_by_forward_into_base_response!(bytestring::ByteString);
 
 macro_rules! impl_into_string_responder {
     ($res:ty) => {
diff --git a/actix-web/src/response/response.rs b/actix-web/src/response/response.rs
index 6449c586d..630acc3f2 100644
--- a/actix-web/src/response/response.rs
+++ b/actix-web/src/response/response.rs
@@ -323,12 +323,6 @@ impl From<Error> for HttpResponse {
 impl<B> From<HttpResponse<B>> for Response<B> {
     fn from(res: HttpResponse<B>) -> Self {
         // this impl will always be called as part of dispatcher
-
-        // TODO: expose cause somewhere?
-        // if let Some(err) = res.error {
-        //     return Response::from_error(err);
-        // }
-
         res.res
     }
 }
diff --git a/actix-web/src/rmap.rs b/actix-web/src/rmap.rs
index 932f7acde..6a1a187b2 100644
--- a/actix-web/src/rmap.rs
+++ b/actix-web/src/rmap.rs
@@ -151,7 +151,7 @@ impl ResourceMap {
                 .char_indices()
                 .filter_map(|(i, c)| (c == '/').then(|| i))
                 .nth(2)
-                .unwrap_or_else(|| path.len());
+                .unwrap_or(path.len());
 
             (
                 Cow::Borrowed(&path[..third_slash_index]),
diff --git a/actix-web/src/test/mod.rs b/actix-web/src/test/mod.rs
index a29dfc437..9c6121151 100644
--- a/actix-web/src/test/mod.rs
+++ b/actix-web/src/test/mod.rs
@@ -5,7 +5,7 @@
 //!
 //! # Off-The-Shelf Test Services
 //! - [`ok_service`]
-//! - [`simple_service`]
+//! - [`status_service`]
 //!
 //! # Calling Test Service
 //! - [`TestRequest`]
@@ -27,7 +27,7 @@ mod test_utils;
 
 pub use self::test_request::TestRequest;
 #[allow(deprecated)]
-pub use self::test_services::{default_service, ok_service, simple_service};
+pub use self::test_services::{default_service, ok_service, simple_service, status_service};
 #[allow(deprecated)]
 pub use self::test_utils::{
     call_and_read_body, call_and_read_body_json, call_service, init_service, read_body,
diff --git a/actix-web/src/test/test_request.rs b/actix-web/src/test/test_request.rs
index fc42253d7..a368d873f 100644
--- a/actix-web/src/test/test_request.rs
+++ b/actix-web/src/test/test_request.rs
@@ -24,10 +24,10 @@ use crate::cookie::{Cookie, CookieJar};
 ///
 /// For unit testing, actix provides a request builder type and a simple handler runner. TestRequest implements a builder-like pattern.
 /// You can generate various types of request via TestRequest's methods:
-///  * `TestRequest::to_request` creates `actix_http::Request` instance.
-///  * `TestRequest::to_srv_request` creates `ServiceRequest` instance, which is used for testing middlewares and chain adapters.
-///  * `TestRequest::to_srv_response` creates `ServiceResponse` instance.
-///  * `TestRequest::to_http_request` creates `HttpRequest` instance, which is used for testing handlers.
+/// - [`TestRequest::to_request`] creates an [`actix_http::Request`](Request).
+/// - [`TestRequest::to_srv_request`] creates a [`ServiceRequest`], which is used for testing middlewares and chain adapters.
+/// - [`TestRequest::to_srv_response`] creates a [`ServiceResponse`].
+/// - [`TestRequest::to_http_request`] creates an [`HttpRequest`], which is used for testing handlers.
 ///
 /// ```
 /// use actix_web::{test, HttpRequest, HttpResponse, HttpMessage};
@@ -42,15 +42,17 @@ use crate::cookie::{Cookie, CookieJar};
 /// }
 ///
 /// #[actix_web::test]
+/// # // force rustdoc to display the correct thing and also compile check the test
+/// # async fn _test() {}
 /// async fn test_index() {
-///     let req = test::TestRequest::default().insert_header("content-type", "text/plain")
+///     let req = test::TestRequest::default().insert_header(header::ContentType::plaintext())
 ///         .to_http_request();
 ///
-///     let resp = index(req).await.unwrap();
+///     let resp = index(req).await;
 ///     assert_eq!(resp.status(), StatusCode::OK);
 ///
 ///     let req = test::TestRequest::default().to_http_request();
-///     let resp = index(req).await.unwrap();
+///     let resp = index(req).await;
 ///     assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
 /// }
 /// ```
diff --git a/actix-web/src/test/test_services.rs b/actix-web/src/test/test_services.rs
index b4810cfd8..e6feea82d 100644
--- a/actix-web/src/test/test_services.rs
+++ b/actix-web/src/test/test_services.rs
@@ -10,11 +10,11 @@ use crate::{
 /// Creates service that always responds with `200 OK` and no body.
 pub fn ok_service(
 ) -> impl Service<ServiceRequest, Response = ServiceResponse<BoxBody>, Error = Error> {
-    simple_service(StatusCode::OK)
+    status_service(StatusCode::OK)
 }
 
 /// Creates service that always responds with given status code and no body.
-pub fn simple_service(
+pub fn status_service(
     status_code: StatusCode,
 ) -> impl Service<ServiceRequest, Response = ServiceResponse<BoxBody>, Error = Error> {
     fn_service(move |req: ServiceRequest| {
@@ -23,9 +23,17 @@ pub fn simple_service(
 }
 
 #[doc(hidden)]
-#[deprecated(since = "4.0.0", note = "Renamed to `simple_service`.")]
+#[deprecated(since = "4.0.0", note = "Renamed to `status_service`.")]
+pub fn simple_service(
+    status_code: StatusCode,
+) -> impl Service<ServiceRequest, Response = ServiceResponse<BoxBody>, Error = Error> {
+    status_service(status_code)
+}
+
+#[doc(hidden)]
+#[deprecated(since = "4.0.0", note = "Renamed to `status_service`.")]
 pub fn default_service(
     status_code: StatusCode,
 ) -> impl Service<ServiceRequest, Response = ServiceResponse<BoxBody>, Error = Error> {
-    simple_service(status_code)
+    status_service(status_code)
 }
diff --git a/actix-web/src/test/test_utils.rs b/actix-web/src/test/test_utils.rs
index 8207ce270..6f0926f35 100644
--- a/actix-web/src/test/test_utils.rs
+++ b/actix-web/src/test/test_utils.rs
@@ -89,7 +89,7 @@ where
 /// ```
 ///
 /// # Panics
-/// Panics if service call returns error.
+/// Panics if service call returns error. To handle errors use `app.call(req)`.
 pub async fn call_service<S, R, B, E>(app: &S, req: R) -> S::Response
 where
     S: Service<R, Response = ServiceResponse<B>, Error = E>,
diff --git a/actix-web/src/web.rs b/actix-web/src/web.rs
index 4858600af..f5845d7f6 100644
--- a/actix-web/src/web.rs
+++ b/actix-web/src/web.rs
@@ -1,4 +1,18 @@
 //! Essentials helper functions and types for application registration.
+//!
+//! # Request Extractors
+//! - [`Data`]: Application data item
+//! - [`ReqData`]: Request-local data item
+//! - [`Path`]: URL path parameters / dynamic segments
+//! - [`Query`]: URL query parameters
+//! - [`Header`]: Typed header
+//! - [`Json`]: JSON payload
+//! - [`Form`]: URL-encoded payload
+//! - [`Bytes`]: Raw payload
+//!
+//! # Responders
+//! - [`Json`]: JSON request payload
+//! - [`Bytes`]: Raw request payload
 
 use std::future::Future;
 
@@ -12,9 +26,7 @@ use crate::{
 
 pub use crate::config::ServiceConfig;
 pub use crate::data::Data;
-pub use crate::request::HttpRequest;
 pub use crate::request_data::ReqData;
-pub use crate::response::HttpResponse;
 pub use crate::types::*;
 
 /// Creates a new resource for a specific path.
diff --git a/awc/Cargo.toml b/awc/Cargo.toml
index 7076897b1..40d9d34b6 100644
--- a/awc/Cargo.toml
+++ b/awc/Cargo.toml
@@ -60,7 +60,7 @@ dangerous-h2c = []
 [dependencies]
 actix-codec = "0.5"
 actix-service = "2.0.0"
-actix-http = { version = "3.0.0-rc.3", features = ["http2", "ws"] }
+actix-http = { version = "3.0.0", features = ["http2", "ws"] }
 actix-rt = { version = "2.1", default-features = false }
 actix-tls = { version = "3", features = ["connect", "uri"] }
 actix-utils = "3.0.0"
@@ -93,13 +93,13 @@ tls-rustls = { package = "rustls", version = "0.20.0", optional = true, features
 trust-dns-resolver = { version = "0.20.0", optional = true }
 
 [dev-dependencies]
-actix-http = { version = "3.0.0-rc.3", features = ["openssl"] }
+actix-http = { version = "3.0.0", features = ["openssl"] }
 actix-http-test = { version = "3.0.0-beta.13", features = ["openssl"] }
 actix-server = "2"
 actix-test = { version = "0.1.0-beta.13", features = ["openssl", "rustls"] }
 actix-tls = { version = "3", features = ["openssl", "rustls"] }
 actix-utils = "3.0.0"
-actix-web = { version = "4.0.0-rc.3", features = ["openssl"] }
+actix-web = { version = "4.0.0", features = ["openssl"] }
 
 brotli = "3.3.3"
 const-str = "0.3"
diff --git a/awc/src/client/pool.rs b/awc/src/client/pool.rs
index 9d130412b..cc3e4d7c0 100644
--- a/awc/src/client/pool.rs
+++ b/awc/src/client/pool.rs
@@ -232,7 +232,7 @@ where
                 None => {
                     let (io, proto) = connector.call(req).await?;
 
-                    // TODO: remove when http3 is added in support.
+                    // NOTE: remove when http3 is added in support.
                     assert!(proto != Protocol::Http3);
 
                     if proto == Protocol::Http1 {