Despite the fact that Firebird 3 has the release candidate now, the majority of Firebird users are still running 2.5 release. Dmitry Yemanov, head of Firebird development, has announced that new minor release of 2.5 was tagged in source code repository:
We encourage all Firebird users migrate to Firebird 2.5.5 as soon as possible. There are several very unpleasant bugs were in Windows builds of 2.5.3 and 2.5.4 releases, which affect performance and stability. These bugs are serious enough that we even prohibited installation of our HQbird tools on these versions on Windows.
So, upgrade your 2.5 version to 2.5.5 asap. It does not require backup/restore (if you are not running at 2.5.1).