diff --git a/action.yml b/action.yml
index c5fdc69..af80755 100644
--- a/action.yml
+++ b/action.yml
@@ -12,10 +12,12 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - uses: DeterminateSystems/nix-installer-action@v4
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         determinate: true
     - uses: DeterminateSystems/magic-nix-cache-action@main
+      with:
+        use-flakehub: false
     - name: Install F*
       shell: bash
       run: nix profile install "$FLAKE"