diff --git a/morph/lib/issuer-aws.nix b/morph/lib/issuer-aws.nix
index 80495e2dc7bafbc9bfbbe174e1a2f75f66942dfe..065e37be07f0b10c22c3608f11f11136fbab11d1 100644
--- a/morph/lib/issuer-aws.nix
+++ b/morph/lib/issuer-aws.nix
@@ -35,5 +35,5 @@
 
   # Turn on automatic optimization of nix store
   # https://nixos.wiki/wiki/Storage_optimization
-  nix.autoOptimiseStore = true;
+  nix.settings.auto-optimise-store = true;
 }