Not sure what you mean - AFAIK, the
DVC perks haven't ever come out as a "package" on a particular date. (The AP/PAP perks do seem to change every year on or near January 1, though). DVC just adds, changes or removes individual perks - I don't think there is any set "length" for any of the DVC perks.
I sure hope that no one at DVC or Disney is thinking of eliminating or reducing the AP/PAP discount - that would be a major disappointment! And a major thrill if they decide to increase it!