DND Whitelisting
If IM Blocking in DND state is enabled, then DND Whitelisting overrides this behavior. If user A in DND state initiates a chat session to user B, user B is added to user A's DND Whitelist. While user B is in user A's DND Whitelist, IMs from user B will be delivered to user A, even if user A is in DND state. When user A closes the chat session with user B, then user B is removed from user A's DND Whitelist.