New Pro Tools software purchases come with a one-year annual upgrade and
support plan. After one year, you have the option of renewing your plan to
continue receiving the latest features. If you choose not to renew, you
can continue using your software indefinitely at the latest version you
have, but will not be able to upgrade it at a later time.
"I have Pro Tools | HD 11, but am not yet on an upgrade and support plan.
Why should I upgrade to Pro Tools 12?"
"...This upgrade also includes an annual upgrade and support plan, so
you'll also receive all future updates, upgrades, and priority support for
one full year, renewable annually. You have until December 31, 2015 to get
on a plan to upgrade your perpetual license and stay current for the next
12 months; otherwise, you will no longer be able to upgrade your software.
And if you want to get early access to Avid Cloud Collaboration for Pro
Tools, you will need to upgrade to Pro Tools 12."