As far as my understanding the issue at that time was inability to process creation
of a database and connecting to it with one query string and that can be solved by
fixing transaction restriction checks for CREATE DATABASE or disallowing multiple
queries in PQexe.
If the issue solved and allowing multiple queries in PQexec doesn’t result in SQL injection
attacks that worth backwards-compatibility breakage by itself the item can be drop or
included to v4 Protocol section if it contains items that break backwards-compatibility already
regards
surafel