diff --git a/README.md b/README.md
index 83034ca..6b0ce38 100644
--- a/README.md
+++ b/README.md
@@ -10,12 +10,12 @@ The Nix Mail setup to rule them all.
 
 ## TODO-List
 
-- [] people should add their puplic keys
-- [] replace keys/test.age
-- [] setup system and init sops
+- [ ] people should add their puplic keys
+- [ ] replace keys/test.age
+- [ ] setup system and init sops
 
 ## Testing Locally
 
 ``
-    nix build
+    $ nix build
 ``
diff --git a/modules/mail.nix b/modules/mail.nix
index 4327244..c9588c7 100644
--- a/modules/mail.nix
+++ b/modules/mail.nix
@@ -1,5 +1,5 @@
 { config, pkgs, ... }:
-let release = "nixos-21.05";
+let release = "nixos-21.11";
 in {
   mailserver = {
     enable = true;