Call of Duty Modern Warfare replaces the 'Prestige' system with more complicated Officer Ranks
You won't have any of your functions or items re-locked in the new Modern Warfare - there's a whole new leveling system.
A new post on the Activision Blog details changes made to the progression system in Call of Duty: Modern Warfare, and how the Prestige system has been replaced. The new system is designed to give players more rewards, and to keep them satisfied and leveling up without needing to reset.
The usual 1-55 levels are your 'Enlisted Ranks', but the Seasonal Officer Ranks are what you'll be pumping your XP into once you hit 55. Once you hit the 55th rank - Command Sergeant Major V - you'll arrive at Officer Rank 1, which will give you 100 new rankings to progress through per season.
Going through the Officer Ranks is a lot like going through the Enlisted Ranks, in that you do it by earning XP. You also get Officer Challenges as you level up, though, and you earn more XP through completing them, which gives you seasons ribbons that can be exchanged for seasonal emblems. Getting through all 100 levels in a season unlocks a weapon blueprint and an animated emblem. Phew.
You'll also be able to earn XP for 'Challenge Missions', multi-step objectives that are accessed and activated in the Barracks menu. Weapons will also have, on average, 50 attachments to unlock, so there's a whole bunch of stuff to earn in Modern Warfare.
The game releases for PC, PS4 and Xbox One on October 25. That's this week!