diff --git a/.github/workflows/nix-action.yml b/.github/workflows/nix-action.yml
index 1856f11..8b54973 100644
--- a/.github/workflows/nix-action.yml
+++ b/.github/workflows/nix-action.yml
@@ -5,7 +5,7 @@ name: Nix CI
 on:
   push:
     branches:
-      - master
+      - v8.19
   pull_request:
     paths:
     - .github/workflows/**
@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         overrides:
-          - 'coq = "master"'
+          - 'coq = "8.19"'
       fail-fast: false
     steps:
       - name: Determine which commit to test