diff --git a/src/py/flwr/server/superlink/state/state.py b/src/py/flwr/server/superlink/state/state.py
index 3090e00a76ba..02209f27957c 100644
--- a/src/py/flwr/server/superlink/state/state.py
+++ b/src/py/flwr/server/superlink/state/state.py
@@ -179,6 +179,7 @@ def store_client_public_key(self, public_key: bytes) -> None:
     def get_client_public_keys(self) -> Set[bytes]:
         """Retrieve all currently stored `client_public_keys` as a set."""
 
+    @abc.abstractmethod
     def acknowledge_ping(self, node_id: int, ping_interval: float) -> bool:
         """Acknowledge a ping received from a node, serving as a heartbeat.
 
diff --git a/src/py/flwr/server/superlink/state/state_test.py b/src/py/flwr/server/superlink/state/state_test.py
index a33f41b1fa17..2bb04c941494 100644
--- a/src/py/flwr/server/superlink/state/state_test.py
+++ b/src/py/flwr/server/superlink/state/state_test.py
@@ -555,7 +555,7 @@ def test_initialize(self) -> None:
         result = state.query("SELECT name FROM sqlite_schema;")
 
         # Assert
-        assert len(result) == 12
+        assert len(result) == 13
 
 
 class SqliteFileBasedTest(StateTest, unittest.TestCase):
@@ -580,7 +580,7 @@ def test_initialize(self) -> None:
         result = state.query("SELECT name FROM sqlite_schema;")
 
         # Assert
-        assert len(result) == 12
+        assert len(result) == 13
 
 
 if __name__ == "__main__":