It's not clear what you are asking.
If you're asking whether there is an upgrade path from a lower version to Photoshop to Photoshop CS6 ( Photoshop 13.x), then the answer is yes. You can upgrade from Cs5 to CS6 perpetual license for $199.00. Just go to the store and, initially ignore the full $699 price. Just click on "Buy" and you'll be presented with a black dropdown menu where you can choose between Full and Upgrade. The dialog will then guide you.
If you want to sign on to the monthly subscription model where you pay every month and never really own Photoshop, then that's just a matter of subscribing, regardless of whether you have a prior version or not.
If you're asking whether you can upgrade from CS6 to a higher version, then the answer is no. There will never be a CS7. In the future it will be by subscription only.