From Dmitry Yemanov: As you might know, Firebird 2.0 no longer allows to alter/drop procedures that are used by active statements. However, we’ve got many requests from customers to restore the previous behaviour, because now it’s impossible to upgrade metadata under load. While we don’t consider this practice safe, I’d like to report that the new limitation is removed in the v2.0.1 release, thus rolling back to the prior logic. All potentially confusing situations (when two different versions of the procedure may coexist in memory simultaneously) are reported in firebird.log.