diff --git a/flake.nix b/flake.nix
index fe76ddcda..1a97e1fcd 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,8 +4,11 @@
     nixpkgs-unstable.url = "flake:nixpkgs/nixos-unstable";
     utils.url = "github:gytis-ivaskevicius/flake-utils-plus/v1.3.1";
     simple-nixos-mailserver = {
-      url = "gitlab:simple-nixos-mailserver/nixos-mailserver/nixos-21.05";
-      inputs.nixpkgs.follows = "nixpkgs";
+      url = "gitlab:simple-nixos-mailserver/nixos-mailserver/nixos-21.11";
+      inputs = {
+        nixpkgs.follows = "nixpkgs-unstable";
+        nixpkgs-21_11.follows = "nixpkgs";
+      };
     };
     dogetipbot-telegram = {
       url = "gitlab:nyanloutre/dogetipbot-telegram/master";