diff --git a/krebs/3modules/exim-retiolum.nix b/krebs/3modules/exim-retiolum.nix
index fc127a414..a18f1c979 100644
--- a/krebs/3modules/exim-retiolum.nix
+++ b/krebs/3modules/exim-retiolum.nix
@@ -37,7 +37,7 @@ let
       config =
         # This configuration makes only sense for retiolum-enabled hosts.
         # TODO modular configuration
-        assert (lib.hasAttr "retiolum" config.krebs.tinc);
+        assert config.krebs.tinc.retiolum.enable;
         ''
           keep_environment =