Norton Security Product Key

I have a not-yet-activated "Norton Security with Backup 10-user key that is valid for one year."   But have 1.5 years of NIS left.  Will the NS key still be valid in 1.5 years?  Or have key activation time-limits been added with NS?  if so, what are they?  ("Valid for one year" wouldn't possibly mean it has to be *activated* in less than one year from now, would it?)