diff --git a/services/nix-cache/harmonia.nix b/services/nix-cache/harmonia.nix
index ddc6319..2e41bc7 100644
--- a/services/nix-cache/harmonia.nix
+++ b/services/nix-cache/harmonia.nix
@@ -1,4 +1,4 @@
-{ config, ... }:
+{ config, unstable, ... }:
 {
   sops.secrets."cache-secret" = {
     sopsFile = ../../secrets/nix-cache01/cache-secret;
@@ -7,6 +7,7 @@
 
   services.harmonia = {
     enable = true;
+    package = unstable.harmonia;
     signKeyPaths = [ config.sops.secrets.cache-secret.path ];
   };
 }