diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 965e78a9..ab4a09bf 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -24,7 +24,7 @@ jobs:
 
   build-unity:
     needs: [update-version-number]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     env:
       UNITY_LICENSE_FILE: ./tmp/ulf
       UNITY_BIN: /opt/Unity/Editor/Unity