MyBB Community Forums

Every time I post a thread, my board takes me to a page saying "Depreciated function call: update_thread_count". When I go back to the forums, the thread's there but on the homepage where it displays the forums where it shows the name, number of posts, and number of threads, my thread number stays as 0.

It also takes me to the same page on newreply.php and so on. it says on the homepage the post count and thread count for the forum is 0

Either you have old plugins that haven't been updated yet (either you or the author needs to update it) or you still have old MyBB files. Try reuploading inc/class_moderation.php

After you have done that you will need to run the 'Rebuild & Recount' tools in the ACP.