Firebird 3 added support for transaction ID to go over, originally, 231 and later 232, all the way up to the 248. Although a great improvement it might become a problem if the client library can’t properly handle that in a few places where these numbers are surfaced.
Because I needed to try this with FirebirdClient too, I needed such database. There isn’t much room for shortcuts (to be really sure it’s a valid database), rather the machine needs to do the work. It took a while to get over 232, which I suppose would be limit most people are interested in. The database I’m providing here (and also archiving it for me in case I need to revisit some code 😃) has Next transaction at
3_300_310_742 over the 232. It’s not a backup of database, but the database file itself, simply because doing backup & restore resets the transaction counter.
Hope it speeds up some of your testing.