Subject RE: [firebird-support] Upgrade Firebird 1.5.3 to 2.5.4 - Using 2.5.4 FB Client to access a 1.5.3 DB database (Follow-Up)
Author Leyne, Sean
> I guess all can tell I’m a little confused on if 32 bit and 64 bit Firebird
> server/client can be mixed and matched for v2.5.4 and if whatever is placed
> onto the work stations would be able to connect to v1.5.3 Firebird server
> running on the old windows 2003 32 bit server.

The Firebird server and client 'bitness' is true mix-and-match -- you can access 32 or 64 bit server from 32 or 64 bit clients without any limitation/restriction.

Separately, you can install 32 bit client or server on 64 bit OS, but can't install 64bit client or server on 32 bit OS.