Microsoft will do some changes for the chat settings in Teams and the policy settings CsTeamsMeetingPolicy and CsTeamsMessagingPolicy. The update MC177121 will start to roll out from April 9th and should be rolled out to all tenants by May 31th. Take time to review your settings if you want chat to remain blocked for users.
Currently you can disable chat for users by using a CsTeamsMessaging policy, so if you wanted to disable chat for users you can assign them to the policy “Disable Chat” (or create a custom policy) and that will disable private chats, group chats and chats in meetings. But if you want to block group chats and private chats but allow chats in meetings that was not possible before this update. In CsTeamsMessagingPolicy is controlled by the setting AllowUserChat.
One example is users in upgrade mode of SfBOnly, SfBWithTeamsCollab, or SfBWithTeamsCollabAndMeetings, they don’t have the Chat app in Teams (since they use chat in Skype) but when attending Teams meetings they should be able to chat in the meeting but they can’t today. The other example is users in TeamsOnly or Islands upgrade mode, their standard settings is to use chat in Teams but administrators might disabled that of some reason, maybe for students, and for these users administrators have to take a new decision if you want to disable chat in meetings (from May 15th).
With this update, MC177121, you will be able to the Enable/Disable chat in CsTeamsMeetingPolicy with the setting MeetingChatEnabledType. If users are in upgrade mode of SfBOnly, SfBWithTeamsCollab, or SfBWithTeamsCollabAndMeetings this setting will have an effect from April 9th, and if MeetingChatEnabledType is enabled in the MeetingPolicy assigned to them they will be able to chat in meetings.
For users in Upgrade mode Islands or Teams Only that today have chat disabled in the
CsTeamsMessaging policy assigned to them will be able to chat in Teams meetings if
MeetingChatEnabledType is enabled, this will take effect from May 15th so that administrator can review settings for users that should not be able to chat.