How to upgrade bbPress? Read the official documentation on upgrading bbPress to be risk-free.
Here is the shortcut I follow which works fine:
1. Download the latest bbPress release and unzip it.
2. Upload the contents of the unzipped folder to your forum folder in the webserver. A BIG WARNING: Don’t upload the whole folder as such to replace the forum folder in webserver. Just upload the contents and add to the files in the forum folder in web server.
Visit your forum URL and follow the instructions.
1. Human test for bbPress – Stops spam registration.
2. Show Top posters – Readers with the most postes are displayed on your bbpress forum, with their names (linked to their website if they provided one).
3. Show display name – Uses the display name as set by WordPress for a bbPress moderator’s name instead of the login name.
4. Auto add favourites – Subscribe to thread whenever you have posted a comment.
5. Post notification – Sends an Notification email if there’s a new post to an favorite topic.
6. Moderator new post notification – Sends a notification e-mail to all moderators and admins if there is a new post from a regular member.