D. Yemanov
Please study this chapter before attempting to install any servers. It is intended as a set of alerts to those who are migrating Firebird 1.0 or 1.5 databases to Firebird 2.0 and higher.
Important: For those who have already done the migration to v.2.0, there are a few more issues that need to be attended to in migrating to v.2.1, in addition to the v.2.0 issues that you have previously taken care of.