diff --git a/matrix_appservice_kakaotalk/kt/types/channel/channel_info.py b/matrix_appservice_kakaotalk/kt/types/channel/channel_info.py
index a72f0d6..a44a2ab 100644
--- a/matrix_appservice_kakaotalk/kt/types/channel/channel_info.py
+++ b/matrix_appservice_kakaotalk/kt/types/channel/channel_info.py
@@ -45,7 +45,7 @@ class ChannelInfo(Channel):
     type: ChannelType
     activeUserCount: int
     newChatCount: int
-    newChatCountInvalid: bool
+    newChatCountInvalid: Optional[bool] = None # NOTE Made optional
     lastChatLogId: Long
     lastSeenLogId: Long
     lastChatLog: Optional[Chatlog] = None