This is not the update that expands the lands of Siptah, this is the update that revamps the already existing lands and content. 
New lands are coming in another update.
Let me quote myself from the same reply
To further specify, we have pointed out the content that has been revamped. i.e. new camps, Vaults reworked, Siptah’s purge. We want players to test that content by participating in it, not by reading a detailed list of what’s new in there. New rewards are given by participating in those activities.