On the bright side, migrating to PlayStation 4 means keeping all of your achievements, subscriptions, unlocks, and so forth as long as you use the same PSN account on both platforms. So you won’t actually lose any progress by upgrading. Still, you’re going to need to upgrade if you’ve been sticking with the console this time; hopefully the upgrade will mean a better experience for players on all platforms and chances for the developers to push for better content.
Source: Official Site; thanks to Greaterdivinity, Jose, ChaosConstant, and Eric for the tip!