It carries the same product name, but is not the same product. So if you are used to utilizing the upgrade offers you are promted with when starting Movie Studio - DONT.
Research this new product and make a decision based on this new product. If you don't like the new product, then there are offers to upgrade to Vegas Pro Edit.
Welcome to the Magix user to user forums.
You are quite correct that MMS 18 is not an upgrade to VMS 17 but is, indeed, a brand new product, based wholly on Magix Movie Edit Pro.
However, there are already a number of posts with a similar message in this forum, including at least one from a member of Magix staff so, with apologies, I am going to close this one in order that we do not see a plethora of similar posts, hopefully! 😀
Jeff
Forum Moderator