One the listing of posts there is a blue indicator on the left of the thread about new posts. If you are in flat mode (the defaultj) then it will automatically take you to the first unread post.
...and the thread is highlighted if a new post has been added. To be honest I will admit not noticing the blue box until it was just mentioned . The thread does go to the next unread post
Re: read vs unread
[Re: leo]
#150999 01/02/201809:03 AM01/02/201809:03 AM
It is the way that the messages are displayed. Flat mode you see all of the messages in the reading window. Threaded mode you have to click on each message to read it.