diff --git a/pkgs/servers/mail/postfix/default.nix b/pkgs/servers/mail/postfix/default.nix
index 6af262567720..92fe6e0403a2 100644
--- a/pkgs/servers/mail/postfix/default.nix
+++ b/pkgs/servers/mail/postfix/default.nix
@@ -24,11 +24,11 @@ let
 
 in stdenv.mkDerivation rec {
   pname = "postfix";
-  version = "3.6.2";
+  version = "3.6.3";
 
   src = fetchurl {
     url = "http://cdn.postfix.johnriley.me/mirrors/postfix-release/official/${pname}-${version}.tar.gz";
-    sha256 = "sha256-UHMj0g17P3BfSc+MB9Q3xtgJC+0H4Vo8DsQF7a1Up9Q=";
+    sha256 = "1g5ii5vvcr87qkabsbyg3n7kzy1g5k2n5gwa8468w5d0ava424hg";
   };
 
   nativeBuildInputs = [ makeWrapper m4 ];