Recover Chat History
This is one of the hardest problems for any end-to-end encrypted app, and XChat is no exception.
Because the private key lives on the original device, moving to a new phone means the new device does not automatically have the old decryption key. In principle, that means it cannot read the previous message history. That is not a flaw unique to XChat. It is a structural consequence of real end-to-end encryption. The same design that keeps the server from reading your messages also makes cross-device recovery more difficult.
Signal deals with this by offering local encrypted backups that can be exported to local or cloud storage and restored later with a backup password. XChat has not publicly confirmed whether it offers a comparable mechanism yet, and that is one of the key things worth watching once the public release settles.
Practical advice for now: before switching devices, check whether XChat offers chat export or encrypted backup. If it does, use it before you migrate. If it does not, be prepared for the possibility that device switching may effectively reset your local history.