diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index c19199c22..47e63c2fb 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -15,3 +15,10 @@ updates:
     open-pull-requests-limit: 5
     labels:
       - "dependencies"
+    ignore:
+      # v4 breaks the docs dispatch with a mismatched Content-Length on
+      # GitHub-hosted runners. Bumping it silently red-mains the docs sync;
+      # this already happened twice (#1049, #1079). Remove once upstream
+      # ships a fixed release.
+      - dependency-name: "peter-evans/repository-dispatch"
+        versions: ["4.x"]
diff --git a/.github/workflows/notify-docs.yml b/.github/workflows/notify-docs.yml
index b03c86c8c..ba2570651 100644
--- a/.github/workflows/notify-docs.yml
+++ b/.github/workflows/notify-docs.yml
@@ -11,12 +11,15 @@ jobs:
   notify:
     runs-on: ubuntu-latest
     steps:
-      # v4 currently sends a mismatched Content-Length for this payload on
-      # GitHub-hosted runners. Keep the last verified release until upstream
-      # resolves the regression.
-      - uses: peter-evans/repository-dispatch@v4
+      # Pinned to v3.0.0 by commit. v4 (v4.0.1) sends a mismatched
+      # Content-Length for this payload on GitHub-hosted runners and fails with
+      # "Request body length does not match content-length header". #1053 pinned
+      # this back once already; a Dependabot bump (#1079) reverted it to v4 and
+      # broke the docs dispatch again. The ignore rule in dependabot.yml keeps
+      # that from recurring. Revisit when upstream ships a fixed v4.
+      - uses: peter-evans/repository-dispatch@ff45666b9427631e3450c54a1bcbee4d9ff4d7c0 # v3.0.0
         with:
           token: ${{ secrets.DOCS_DISPATCH_TOKEN }}
-          repository: OpenAdaptAI/openadapt-maintenance
+          repository: OpenAdaptAI/openadapt-ops
           event-type: repo-updated
           client-payload: '{"repo": "${{ github.repository }}", "sha": "${{ github.sha }}"}'