AutoCAD is gong the subscription model: pay now or pay later, that's your choice.
If you do it before that deadline, and your current seat is eligible for a discount to upgrade, you'll simply add the cost of joining the subscription to it. You decide if you want to change versions every year or not, it really depends on your workflows.
If you wait until after the subscription, everyone (whether your version of AutoCAD is one year old or 20-years old or if you've never owned it) pays full price plus the subscription fee to get a newer version.
You should be working with a reseller in your area to keep an eye out for pricing specials and other discounts that might get you on board that subscription bus cheaper than list price.
As always, since you are the customer, you have the option to stay where you are: your current license is valid for you to use forever (or until Microsoft changes the OS dramatically again). Or you could go off the reservation completely: lots of knock-offs that hark back to that classic 1999 look/feel out there.
