This release contains a new major feature to further integrate corporate setups: Email notification about room invites when doing via Matrix ID.
Currently, if you are inviting someone to a room using a 3PID which is present in a configured Identity store, there are no notification of the invite if the account is not yet provisioned into synapse.
This is especially problematic for on-boarding invites, where users need to be told separately about the new service or invites.
This feature ensures they are always notified.
Read the documentation for further details.