Every porter you saved: their photo, name and nickname, where they work, and your stars for the last time they helped. Kept on your free Dockside account. Export a backup before you switch phones — this account is not yet recoverable on a new device any other way.
Saved messages →Export saves a small file — email it to yourself, save it to Files or Drive, whatever you'd use for any other file. Import reads that file back in on a new phone.