Hi! In v4 RC1 zip kits for Windows, there is duplicated boost directory.
One in include/firebird/impl/boost (correct) and another in include/firebird/boost (incorrect). In recent GitHub actions artifacts, I see it's not there. But I don't see anything explicit in the logs since RC1, so I'm not sure there is a difference in how the official build is done. Adriano Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel