2 years' worth of NIS license keys: useless in the long run?

Hello all,

A couple of years ago, I forget the exact date, I was able to purchase a group of boxed copies of NIS for Windows for a nice discount, obviously before it was announced that NIS would be discontinued in favor of the unified Norton Security line. My current license expires in September, and I am now wondering how long NIS support will continue, in light of the fact that I have sealed and unused licenses to last through September 2017, and any holders of NIS licenses will be, at least to my understanding, not allowed to upgrade to the new product using their current NIS licenses.

Will NIS legacy support continue for this length of time? If not, who would be the best contact to see if there is something that can be worked out for my situation? Norton phone support? Chat?

If anyone from the Norton community or Symantec can help clarify this situation, I'd be most appreciative. Essentially, I'm hoping that some resolution can be reached so that I'm not out the money for the licenses that I have.