Theres a couple of new settings there with options you can toggle to choose, and save so they stay as your default.
Select subscription as default
Select the time limit for pages
'Since Last Visit' behaves basically like 'new posts' in that it will show posts that you havent navigated to before.
I like to set it a little longer so i see more threads than that, including other more recent ones i mightve already read but didnt get around to replying to and wanted to later on... but its personal preference.
You can also toggle the time limit for pages at the top of the forum pages to your liking, this will only stay that way for your current browsing session when toggled from there.
Important note on that setting.. it seems to be set to 'Yes' automatically for everyone.
So if you dont set it to no, it will be different to before... and now the little box will be ticked near where you submit posts, and users will get emails and be subscribed to the threads.
So I suggest peeps set it to no if they dont want the emails coming.
'Favouriting' a topic does a similar job to subscribing to it, in that you can find the topics you want easily using the forum tabs... but with favourites you wont get the reminder emails, with subscriptions you do, thats the difference.