On my version of TapaTalk app there are tabs for, Trending, Subforums, Timeline, Unread, Subscribed, Participated. Timeline are the most recent. The little 3 dot pull down menu(top right) also has a refresh to update the Timeline so that you know your looking at the newest on the top of the list. Of course I don't update things that probably aren't broken to begin with so my app may be old an outdated. Make sure you've chosen Home on the hamburger pull down menu, top left.
I'm sure my older version it had a " New posts " section for any new posts regardless of the section they were posted in. I'm now having to go through the home page and look at each sub section.
Cheers.