diff --git a/.github/workflows/ci-cpu-linux.yml b/.github/workflows/ci-cpu-linux.yml
index 4622a4b26..ac18a8034 100644
--- a/.github/workflows/ci-cpu-linux.yml
+++ b/.github/workflows/ci-cpu-linux.yml
@@ -45,12 +45,12 @@ jobs:
 
     steps:
     - name: Checkout pbrt
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
     - name: Checkout rgb2spectrum tables
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: mmp/rgb2spectrum
         path: build
diff --git a/.github/workflows/ci-cpu-macos.yml b/.github/workflows/ci-cpu-macos.yml
index 10959b25e..85cfaf6bd 100644
--- a/.github/workflows/ci-cpu-macos.yml
+++ b/.github/workflows/ci-cpu-macos.yml
@@ -23,12 +23,12 @@ jobs:
 
     steps:
     - name: Checkout pbrt
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
     - name: Checkout rgb2spectrum tables
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: mmp/rgb2spectrum
         path: build
diff --git a/.github/workflows/ci-cpu-windows.yml b/.github/workflows/ci-cpu-windows.yml
index 6455c5e4a..de8667cf4 100644
--- a/.github/workflows/ci-cpu-windows.yml
+++ b/.github/workflows/ci-cpu-windows.yml
@@ -23,12 +23,12 @@ jobs:
 
     steps:
     - name: Checkout pbrt
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
     - name: Checkout rgb2spectrum tables
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: mmp/rgb2spectrum
         path: build
diff --git a/.github/workflows/ci-gpu.yml b/.github/workflows/ci-gpu.yml
index 0e8a9a56f..ecdf0b363 100644
--- a/.github/workflows/ci-gpu.yml
+++ b/.github/workflows/ci-gpu.yml
@@ -35,12 +35,12 @@ jobs:
       run: nvcc -V
 
     - name: Checkout pbrt
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         submodules: true
 
     - name: Checkout rgb2spectrum tables
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: mmp/rgb2spectrum
         path: build
@@ -52,7 +52,7 @@ jobs:
         key: optix-7.12345
 
     - name: Checkout OptiX headers
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         ssh-key: ${{ secrets.CHECKOUT_KEY }}
         repository: mmp/optix-headers