3.2.1. Before installation

It is almost always advisable to uninstall any previous Firebird installations completely (after you’ve read the next paragraph!) and also hunt the Windows system dirs for old copies of gds32.dll and fbclient.dll. If you’re using Linux, the uninstall scripts should have removed any copies and/or symlinks in /usr/lib[64], but it won’t hurt to look if anything named libfbclient. or libgds. is still lying around.

Furthermore, you should be aware that Firebird 3 won’t open databases that were created by older versions. So before taking down your existing setup, you should back up all your databases in order that you can restore them later under Firebird 3.

You may also want to back up your old security database security2.fdb. Firebird 3 comes with an SQL script security_database.sql (located in misc/upgrade/security) that will upgrade the old security database to Firebird 3, preserving all information except SYSDBA‘s and except any passwords. For more information, see Compatibility Issues :: Upgrading a v.2.x Security Database in the Firebird 3 Release Notes.