Hi Sunit Carpenter,
Thanks for your question.
It depends on the license type you purchased. We have two types of Developer license - with or without subscription. To check how they differ you can check the Silverlight product - purchase page.
In other words, the license with subscription entitles you for all the minor and major versions throughout the year. The Developer license without subscription does not include new major versions. You can check Renewals & Upgrades for more details and options that you have.
the Telerik team