diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index dc156ce8..173a3bc8 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -15,6 +15,20 @@ updates:
     groups:
       routine:
         update-types: ["patch", "minor"]
+    # Major versions of these four break the current stack (numpy 2.x fails at
+    # import under opencv-python 4.8; zarr 3 and opencv 5 change their APIs). Left
+    # unignored they each hold a slot in open-pull-requests-limit indefinitely,
+    # which on 2026-09-01 blocked the numpy update that was actually needed. They
+    # are taken deliberately, by editing the pin, not by Dependabot.
+    ignore:
+      - dependency-name: "numpy"
+        update-types: ["version-update:semver-major"]
+      - dependency-name: "opencv-python"
+        update-types: ["version-update:semver-major"]
+      - dependency-name: "opencv-python-headless"
+        update-types: ["version-update:semver-major"]
+      - dependency-name: "zarr"
+        update-types: ["version-update:semver-major"]
     commit-message:
       prefix: "chore(deps)"