There seems to be a bug in "db_driverkey", when OpenACS connects to multiple databases [1]. The situation with "db_driverkey" is complicated by the fact that this function is sometimes called with a database name in its argument "dbn", and sometimes with a database handle. This is something to look at in the future.
The new version removes the per-thread caching, which was introduced to reduce the high number of mutex locks caused in busy machines. The new version is better by a factor of 2 than older versions, but relies on NaviServer.
ns_mktemp uses the deprecated old POSIX call mktemp(), which should not be used anymore for security reasons (race between the name creation and opening the file). This change removes several usages of "ns_mktemp" from OpenACS and replaces it with calls to the safe Tcl call "file tempfile ..." (introduced by Tcl 8.6).