Re: Upgrade problems
Check these related posts, all tagged with 745:
https://bbpress.org/forums/tags/745
745 is the trac ticket where the bug was recorded:
https://trac.bbpress.org/ticket/745
There is a patch attached to that ticket that seems to solve the problem:
https://trac.bbpress.org/attachment/ticket/745/745c.diff
Upon reading more closely your report, this may not be related to your problem at all. I don’t know if I’ve ever seen your problem before. It is sort of related since it’s about db-mysqli.php and db.php. Maybe that patch will fix things up for you.