First of all, thank you to everyone for their patience. I know I promised this a while ago but I have only recently had time to finish this off. Specifically I would like to thank @Azhria Lilu, @The Sandman, @MattW and @Martok for giving this some testing.
The most important feature of this release is the new caching feature. This should drastically improve the number of hits your database gets as the Unread Post Count is now cached for 1 minute by default in the visitor's session. Should you wish to increase the cache time, you can find the setting in Admin CP > Options > Threads, Discussions and Conversations:
There is a chance that this could still perform poorly on extremely busy boards or databases that aren't optimised. Changing the cache time up will help, but ultimately each of your logged in members will still be running quite a heavy query every X minutes.
Finally, the annoying bug which counted unread posts in deleted threads has been resolved.
