diff --git a/ably/realtime/connection.py b/ably/realtime/connection.py
index 179e4a6b..6cf3490f 100644
--- a/ably/realtime/connection.py
+++ b/ably/realtime/connection.py
@@ -3,7 +3,7 @@
 import websockets
 import json
 from ably.util.exceptions import AblyAuthException
-from enum import Enum
+from enum import Enum, IntEnum
 
 log = logging.getLogger(__name__)
 
@@ -17,7 +17,7 @@ class ConnectionState(Enum):
     FAILED = 'failed'
 
 
-class ProtocolMessageAction(Enum):
+class ProtocolMessageAction(IntEnum):
     CONNECTED = 4
     ERROR = 9