Never really knew it as I guess I never tried before. But apparently you're unable to make an attachment within the PM system. Well that sucks!
So now you can! When sending a PM or replying to someone - look at the very bottom of the options and you'll see "Manage Attachments", and you can include one in the same manner as making a post.
A few other additions you will see:
When you now go to your Inbox - the sender of the PM's will show a small version of that member's avatar.
Move your mouse over the title of any PM and a preview box will pop up showing the first few lines of the PM.
At the very top you will first see a table that displays: How many messages in your inbox, how many messages stored in total & how many you have allowed and a percentage of used. And additionally, now an option to easily download all of your messages should you want to. (and a folder picker in the upper right of that table with a drop down arrow).
Haven't seen it yet as I haven't gotten a PM since, but: Apparently a different notification when you have one waiting & supposedly blinking at the top. I'll wait to see how annoying that appears.
Getting a PM if a member is quoted in a post. Someone asked for this about 7 or 8 years ago or so, here it is!!
Then a few more additions on the back end.
Lemme know or report here any issues.