As I understand it, a major update for the Android version is also in the near future. Since Christmas will mark 2 years since the first version hit the streets, it does make sense for long time users to pay for this major upgrade..
But how about short timers, someone who buys the program today, in two or three months, they may need to buy the new version..
I copied this from Tech Radar tonight:
Until Android 4.4 was announced we had expected the Android 5.0 release date to be some time in October 2013. We now expect to see Android 4.4 KitKat launch during that month. In the face of that point release, we think it's now likely that we'll see Android 5.0 shown in mid-2014, quite possibly at Google IO, Google's annual two-day developer conference in San Francisco.