diff --git a/.github/workflows/master.yml b/.github/workflows/master.yml
index ecac3f7..640ce08 100644
--- a/.github/workflows/master.yml
+++ b/.github/workflows/master.yml
@@ -19,7 +19,7 @@ jobs:
     - name: Install Nix
       uses: cachix/install-nix-action@v26
       with:
-        nix_path: nixpkgs=channel:nixos-20.09
+        nix_path: nixpkgs=channel:nixos-23.05
 
     - name: Build book
       run: |
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 66fc13c..5ce99e8 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -18,7 +18,7 @@ jobs:
     - name: Install Nix
       uses: cachix/install-nix-action@v26
       with:
-        nix_path: nixpkgs=channel:nixos-20.09
+        nix_path: nixpkgs=channel:nixos-23.05
 
     - name: Build book
       run: |