[@robkk Moderator 11 years, 6 months ago]

@pazzaglia1

is it just the search or is it bbPress entirely??

As long as you have the latest bbPress too it should work fine.

usually users that have problems with bbPress when upgrading to WP 4 , we usually recommend these two plugins to help solve their issue.

bbpress wp4 fix

bbpress wp4 fix2

you can also go through the normal troubleshooting to identify an issue.

bbpress.org/forums/topic/before-posting/