diff --git a/flake/overlay.nix b/flake/overlay.nix
index 22ae40f..c53b06d 100644
--- a/flake/overlay.nix
+++ b/flake/overlay.nix
@@ -10,8 +10,9 @@ final: prev: {
     bij;
   inherit (chaosevents.packages.${final.system})
     chaosevents;
-  inherit (harmonia.packages.${final.system})
-    harmonia;
+  harmonia = harmonia.packages.${final.system}.harmonia.override {
+    nixForHarmonia = final.nixVersions.nix_2_21;
+  };
   inherit (ssh-to-age.packages.${final.system})
     ssh-to-age;
 }