I was all confused finding old threads coming first today, so I went to the Webmaster forum and here is his/her answer:
Some of you have already seen that forum threads are behaving differently than before.
In the past, forum threads were organized by the time of the topic message.
That means that threads were always ordered chronologically, as they appeared in the forum.
As a result, if someone posted a reply to a thread that is not on the last page, it was not easy to see that reply, unless you would click on the "Last Message" link.
From today, default view for the forum threads is different.
If a new message is posted on a 12 years old thread, that thread still "jumps"-up to the top of the last forum page, making it easy to find and see that message.
Can I still view forums in the old view?
There is a link on the forum menu, called
If you click on that link, you will get the threads organized like before.
To come back to the "NEW ORDER", just click on the forum menu item called "NEW ORDER".
Both links "OLD ORDER" and the "NEW ORDER" are on the same place.
You can still expand both "OLD ORDER" and the "NEW ORDER" pages by clicking on the link "EXPAND".
And You can still collapse both "OLD ORDER" and the "NEW ORDER" pages by clicking on the link "COLLAPSE".