diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index f18d3fe7..65213714 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -9,3 +9,5 @@ Simon Richardson
 Jack Shaw
 Leon Mintz
 Adam Dyess
+---
+Dummy change, don't merge
diff --git a/tests/base.py b/tests/base.py
index 72151c2a..19187b2d 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -79,6 +79,12 @@ async def __aenter__(self):
         model_name = f"test-{test_run_nonce}-{test_name}-{model_nonce}"
         self._model = await self._controller.add_model(model_name)
 
+        # Some charms used for testing are not yet available for 24.04
+        await self._model.set_config({
+            "default-base": "ubuntu@22.04",
+            # "default-series": "jammy",  # not allowed to set both
+        })
+
         # Change the JujuData instance so that it will return the new
         # model as the current model name, so that we'll connect
         # to it by default.