I think it's important for the user to know since now they have to trust a new server. And the group may have forked while moving (it may have moved to two different conflicting places, for example). I also think in many cases the migration will happen manually and integrants will rearrange by word-of-mouth.
Maybe we can define a kind:29 event that any group member can publish signaling where is (are) the canonical location(s) of the group "xyhdffqa". If before it existed on groups.telegram.org and now it exists on groups.discord.com. Then clients may try to fetch these events from outbox relays of previous members when they can't connect to a specific relay or when a group is behaving weird for any reason?
