diff --git a/.github/workflows/sync-arena-configs.yml b/.github/workflows/sync-arena-configs.yml
index 35a4710..f7e0d23 100644
--- a/.github/workflows/sync-arena-configs.yml
+++ b/.github/workflows/sync-arena-configs.yml
@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: Checkout webDisplayTools
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
         uses: actions/setup-node@v7
@@ -91,7 +91,7 @@ jobs:
 
       - name: Create Pull Request
         if: steps.changes.outputs.changed == 'true'
-        uses: peter-evans/create-pull-request@v5
+        uses: peter-evans/create-pull-request@v8
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           commit-message: "chore: sync arena configs from maDisplayTools"
diff --git a/.github/workflows/validate-calculations.yml b/.github/workflows/validate-calculations.yml
index 9ecb2d4..0924be5 100644
--- a/.github/workflows/validate-calculations.yml
+++ b/.github/workflows/validate-calculations.yml
@@ -24,10 +24,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v7
         with:
           node-version: '24'
 
diff --git a/.github/workflows/validate-g6-encoding.yml b/.github/workflows/validate-g6-encoding.yml
index 6f87525..f54178c 100644
--- a/.github/workflows/validate-g6-encoding.yml
+++ b/.github/workflows/validate-g6-encoding.yml
@@ -24,10 +24,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v7
         with:
           node-version: '24'
 
diff --git a/.github/workflows/validate-pattern-generation.yml b/.github/workflows/validate-pattern-generation.yml
index 47175b2..47e6215 100644
--- a/.github/workflows/validate-pattern-generation.yml
+++ b/.github/workflows/validate-pattern-generation.yml
@@ -29,10 +29,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v7
         with:
           node-version: '24'
 
diff --git a/.github/workflows/validate-protocol-roundtrip.yml b/.github/workflows/validate-protocol-roundtrip.yml
index 1fce94a..74ea091 100644
--- a/.github/workflows/validate-protocol-roundtrip.yml
+++ b/.github/workflows/validate-protocol-roundtrip.yml
@@ -50,10 +50,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v7
         with:
           node-version: '24'
 
diff --git a/js/arena-configs.js b/js/arena-configs.js
index acdc8c2..e3d3ddf 100644
--- a/js/arena-configs.js
+++ b/js/arena-configs.js
@@ -1,7 +1,6 @@
 /**
  * Arena Configurations
  * Auto-generated from maDisplayTools/configs/arenas/ and arena_registry/
- * Last updated: 2026-07-19T01:25:01.029Z
  *
  * DO NOT EDIT MANUALLY - regenerate with: node scripts/generate-arena-configs.js
  */
diff --git a/scripts/generate-arena-configs.js b/scripts/generate-arena-configs.js
index 5091f24..3940475 100644
--- a/scripts/generate-arena-configs.js
+++ b/scripts/generate-arena-configs.js
@@ -256,11 +256,14 @@ function main() {
     }
     const registryStr = registryLines.join(',\n');
 
-    // Generate output
+    // Generate output. Deliberately NO generation timestamp in the header: it made
+    // every run of the sync-arena-configs workflow a "change" and opened a weekly PR
+    // whose entire diff was that one line (e.g. #169). Output must stay a pure function
+    // of the input YAML so "Check for changes" means a real config change. Git history
+    // records when the file last changed; don't re-add a Date here.
     const output = `/**
  * Arena Configurations
  * Auto-generated from maDisplayTools/configs/arenas/ and arena_registry/
- * Last updated: ${new Date().toISOString()}
  *
  * DO NOT EDIT MANUALLY - regenerate with: node scripts/generate-arena-configs.js
  */