diff --git a/.github/workflows/debug.yml b/.github/workflows/debug.yml
index 1715c8e..c047035 100644
--- a/.github/workflows/debug.yml
+++ b/.github/workflows/debug.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: macos-10.15
     steps:
     - uses: actions/checkout@v2
-    - uses: cachix/install-nix-action@v8
+    - uses: cachix/install-nix-action@v9
     - run: |
         nix-channel --update
         echo "FIXME workaround channel permission error"
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a4b9f13..765ed3f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,7 +8,7 @@ jobs:
     timeout-minutes: 10
     steps:
     - uses: actions/checkout@v2
-    - uses: cachix/install-nix-action@v8
+    - uses: cachix/install-nix-action@v9
     - run: nix-build ./release.nix -I darwin=. -A tests
     - run: nix-build ./release.nix -I darwin=. -A manpages
     - run: nix-build ./release.nix -I darwin=. -A examples.simple