Change author 3.4

Change author v3.4 changes:

Fixed issue with Latest post not being updated if changing author of last post in the thread.

Change author v3.3 changes:

Fixed issue with updating attachment data.

Change author v3.2 changes:

Fixed issue with last post information shown in forum view.

Change author v3.1 changes:

Now updates thread watch.

Change author v3.0 changes:

Fixed issue with properly updating news feed data.

Change author v2.9 changes:

Fixed issue with xf_news_feed empty condition.

Change author v2.8 changes:

Fixed issue with Latest activity not being updated.

Change author v2.7 changes:

Fixed issue with changing guest author.

Change author v2.6 changes:

Fixed issue with xf_thread_read and xf_thread_user_post counts.

Change author v2.5 changes:

Now updates the search index and user post counts.