diff --git a/actix-server/Cargo.toml b/actix-server/Cargo.toml
index da7d792e..4e0f2aff 100755
--- a/actix-server/Cargo.toml
+++ b/actix-server/Cargo.toml
@@ -30,7 +30,7 @@ log = "0.4"
 mio = { version = "0.7.6", features = ["os-poll", "net"] }
 num_cpus = "1.13"
 slab = "0.4"
-tokio = { version = "1.2", features = ["sync"] }
+tokio = { version = "1.4", features = ["sync"] }
 
 [dev-dependencies]
 actix-codec = "0.4.0-beta.1"
diff --git a/actix-server/src/server.rs b/actix-server/src/server.rs
index 6b9a294f..f37f2867 100644
--- a/actix-server/src/server.rs
+++ b/actix-server/src/server.rs
@@ -75,7 +75,7 @@ impl Server {
                 // construct signals future.
                 let signals = if !builder.no_signals {
                     // Check tokio runtime.
-                    if tokio::runtime::Handle::try_current().is_err() {
+                    if !is_tokio {
                         let err = io::Error::new(io::ErrorKind::Other, "there is no reactor running. Please enable ServerBuilder::disable_signals when start server in non tokio 1.x runtime.");
                         return Self::Error(Some(err));
                     }
diff --git a/actix-server/src/worker.rs b/actix-server/src/worker.rs
index e203462a..ffb0fa6d 100644
--- a/actix-server/src/worker.rs
+++ b/actix-server/src/worker.rs
@@ -224,6 +224,7 @@ impl ServerWorker {
             .unwrap_or_else(|| Ok(handle_pair(idx, tx1, tx2, avail)))
     }
 
+    // TODO: Use start_non_blocking when restarting worker.
     #[allow(dead_code)]
     /// Start server worker in async.
     pub(crate) fn start_non_blocking(