diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f1d18007b..9ba5dd8c4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4      
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
@@ -24,7 +24,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
@@ -39,7 +39,7 @@ jobs:
       matrix: ${{ steps.job-matrix.outputs.matrix }}
     steps:
     - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
@@ -55,7 +55,7 @@ jobs:
       matrix: ${{ steps.job-matrix.outputs.matrix }}
     steps:
     - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
@@ -72,7 +72,7 @@ jobs:
       matrix: ${{ fromJson(needs.pkgs_x86_64_linux.outputs.matrix) }}
     steps:
     - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
diff --git a/.github/workflows/claude.yml b/.github/workflows/claude.yml
index 806ab3f97..4e0421faa 100644
--- a/.github/workflows/claude.yml
+++ b/.github/workflows/claude.yml
@@ -30,7 +30,7 @@ jobs:
         with:
           fetch-depth: 1
 
-      - uses: DeterminateSystems/nix-installer-action@v20
+      - uses: DeterminateSystems/nix-installer-action@v21
         with:
           extra-conf: |
             accept-flake-config = true
diff --git a/.github/workflows/hcloud-cost-mgmt.yaml b/.github/workflows/hcloud-cost-mgmt.yaml
index 72f2ffb5f..e70b7b326 100644
--- a/.github/workflows/hcloud-cost-mgmt.yaml
+++ b/.github/workflows/hcloud-cost-mgmt.yaml
@@ -24,7 +24,7 @@ jobs:
     - name: Set up Cloud SDK
       uses: google-github-actions/setup-gcloud@v2
 
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
diff --git a/.github/workflows/hcloud-dev.yaml b/.github/workflows/hcloud-dev.yaml
index d03d675cb..8e022789b 100644
--- a/.github/workflows/hcloud-dev.yaml
+++ b/.github/workflows/hcloud-dev.yaml
@@ -41,7 +41,7 @@ jobs:
     - name: Set up Cloud SDK
       uses: google-github-actions/setup-gcloud@v2
 
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true
diff --git a/.github/workflows/update.yaml b/.github/workflows/update.yaml
index 383de73e8..d2c396f14 100644
--- a/.github/workflows/update.yaml
+++ b/.github/workflows/update.yaml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@v20
+    - uses: DeterminateSystems/nix-installer-action@v21
       with:
         extra-conf: |
           accept-flake-config = true