Subject RE: [IBO] Migrating to IBO 4.9
Author Support List

> The version 4.9 release 14 is compatible with Firebird 1.5x?

There was a bug that got introduced but it is fixed now.

> I have problems with using Firebird 1.5x / IBO 4.9?

You shouldn't. All versions of FB are officially supported by IBO 4.9.x.