If the invitee opens the invitation URI and chooses to create a new - account, the client MUST use the inviter's server as default if the - server advertises in-band registration support via the - ibr=y query compontent.
+If the invitee opens an invitation URI with ibr=y and + chooses to create a new account, the client SHOULD pre-fill the + inviter JID's domain part as the new account's domain. The client MAY + provide a mechanism to enter or choose a different server, though.