kinterbasdb-3.1.1 is now available. This is a maintenance release of the stable 3.1 branch.
Note that the Win32 binaries of KInterbasDB linked against the Firebird 1.5 client library (fbclient.dll) also work with (prereleases of) Firebird 2.0; their filenames indicate this.
Changelog:
http://kinterbasdb.sourceforge.net/dist_docs/changelog.txt
Download:
http://sourceforge.net/project/showfiles.php?group_id=9913&package_id=10717&release_id=329289