diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index cc99008..6ff1b5f 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        smalltalk: [ Pharo64-8.0, Pharo64-7.0 ]
+        smalltalk: [ Pharo64-9.0, Pharo64-8.0, Pharo64-7.0 ]
     name: ${{ matrix.smalltalk }}
     steps:
       - uses: actions/checkout@v2