diff --git a/.fixme/config b/.fixme/config
index 0f316f8f..f0dc67c2 100644
--- a/.fixme/config
+++ b/.fixme/config
@@ -4,9 +4,12 @@ fixme-comments  --
 
 fixme-prefix     FIXME:     bugs issues
 fixme-prefix     TODO:      bugs issues
+fixme-prefix     PEP:       proposals
 
 fixme-files **/*.hs docs/devlog.md
 
+fixme-files docs/pep*.txt
+
 fixme-files-ignore .direnv/** dist-newstyle/**
 
 fixme-id-show-len 10
diff --git a/docs/pep-01.txt b/docs/pep-01.txt
new file mode 100644
index 00000000..02ce28d0
--- /dev/null
+++ b/docs/pep-01.txt
@@ -0,0 +1,6 @@
+PEP: block-encrypting-data-structures
+
+ Here we define a data structures, required for implementing
+ basic encrypted blocks exchange
+
+
diff --git a/flake.lock b/flake.lock
index d2dd1f6c..2f884147 100644
--- a/flake.lock
+++ b/flake.lock
@@ -3,15 +3,17 @@
     "fixme": {
       "inputs": {
         "haskell-flake-utils": "haskell-flake-utils",
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
         "suckless-conf": "suckless-conf"
       },
       "locked": {
-        "lastModified": 1675929344,
-        "narHash": "sha256-iytvSV60QF7xNWZKcljjMknSgU3uwAcqqlNiqGRzRLQ=",
+        "lastModified": 1675932962,
+        "narHash": "sha256-EmAstwsWB7WQVl4w3a1SaJ6dGw1KH3G/0Q6zgkvwDgs=",
         "owner": "voidlizard",
         "repo": "fixme",
-        "rev": "e9bb7ccb97649db13b519aa79d1f36bdd1dda55d",
+        "rev": "50c9501e7ea8ff9838f1c340c8c97cbb6bcd8736",
         "type": "github"
       },
       "original": {
@@ -176,21 +178,6 @@
       }
     },
     "nixpkgs": {
-      "locked": {
-        "lastModified": 1675760670,
-        "narHash": "sha256-do2YGWoNUEPnmE0gWkdGJqsfQ2ARJOkzIfWt+gSpNbA=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "e63fe191354ccc082199b550980e346597c52282",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs_2": {
       "locked": {
         "lastModified": 1675758091,
         "narHash": "sha256-7gFSQbSVAFUHtGCNHPF7mPc5CcqDk9M2+inlVPZSneg=",
@@ -205,7 +192,7 @@
         "type": "github"
       }
     },
-    "nixpkgs_3": {
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1675931149,
         "narHash": "sha256-UcsoOsP9tDlENB1KKdr9EgSmA124id6OxpHb7IpHlD8=",
@@ -225,7 +212,7 @@
         "fixme": "fixme",
         "haskell-flake-utils": "haskell-flake-utils_3",
         "hspup": "hspup",
-        "nixpkgs": "nixpkgs_3",
+        "nixpkgs": "nixpkgs_2",
         "saltine": "saltine"
       }
     },
@@ -249,7 +236,7 @@
     "suckless-conf": {
       "inputs": {
         "haskell-flake-utils": "haskell-flake-utils_2",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": "nixpkgs"
       },
       "locked": {
         "lastModified": 1675928120,
diff --git a/flake.nix b/flake.nix
index 08fd1285..849d74de 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,7 +10,7 @@ inputs = {
     hspup.inputs.nixpkgs.follows = "nixpkgs";
 
     fixme.url = "github:voidlizard/fixme";
-    # fixme.inputs.nixpkgs.follows = "nixpkgs";
+    fixme.inputs.nixpkgs.follows = "nixpkgs";
 
     saltine = {
       url = "github:tel/saltine/3d3a54cf46f78b71b4b55653482fb6f4cee6b77d";