diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index 6f530f2..94c8518 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -915,6 +915,7 @@ in
 
   services.mattermost = {
     enable = true;
+    package = pkgs.callPackage ./mattermost {};
     siteUrl = "https://chat.m-labs.hk/";
     mutableConfig = true;
   };