diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 09c5112..5728e7c 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -24,6 +24,9 @@ updates:
     ignore:
       - dependency-name: "*"
         update-types: ["version-update:semver-patch"]
+      # Its tags are Rust toolchain versions, not action releases: the MSRV
+      # job pins the declared minimum and must never be "upgraded".
+      - dependency-name: "dtolnay/rust-toolchain"
     open-pull-requests-limit: 5
     commit-message:
       prefix: "ci"
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 89502c8..62ebd91 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v7
         with:
           submodules: recursive
-      - uses: dtolnay/rust-toolchain@1.120.0
+      - uses: dtolnay/rust-toolchain@1.91.0
       - name: Install native hotkey and capture prerequisites
         run: |
           sudo apt-get update