The Automattic team today released bbPress 0.9, an upgrade that makes this forum software compatible with WordPress 2.5, supports Gravatars (or profile images) and generates cleaner and more SEO friendly URLs.
The process of upgrading your old bbPress installation to the new bbPress 0.9 database is simple but once the upgrade is complete, you could have trouble logging in especially into the admin dashboard.
I don’t know the exact technical reason but this has something to do with the way passwords are now stored in bbPress database - they were earlier using md5 but have now shifted to phppass.
Anyways, if you are also getting this error message “Fatal error: Call to undefined function wp_set_password() in /bb-includes/pluggable.php on line 368” when trying to login into bbpress, here’s a simple fix.
1. Open the home page of your forum and type your user name. Then type some junk password which is different from your actual password. Click log-in.
2. bbPress will show a page saying “Login Failed”. Perfect. This page has a button saying “Recover Password”.
Click this and bbPress will reset your existing password and email back a new password. You can now login into bbPress without problems.