diff --git a/.github/workflows/regression-tests.yml b/.github/workflows/regression-tests.yml
index 4c78aa3..c3820aa 100644
--- a/.github/workflows/regression-tests.yml
+++ b/.github/workflows/regression-tests.yml
@@ -4,12 +4,12 @@ on: [push, pull_request]
 
 jobs:
   build:
-    name: Python (${{ matrix.group }}/10)
+    name: Python (${{ matrix.group }}/20)
     runs-on: ubuntu-24.04
     
     strategy:
       matrix:
-        group: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+        group: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
 
     steps:
     - uses: actions/checkout@v3
@@ -23,4 +23,4 @@ jobs:
         pip install tox tox-gh-actions
 
     - name: Test with tox
-      run: tox -- -n auto --verbose --splits 10 --group ${{ matrix.group }} --splitting-algorithm least_duration
+      run: tox -- -n auto --verbose --splits 20 --group ${{ matrix.group }} --splitting-algorithm least_duration