Halo 4 challenges have been down since Jan. 1, 2016. While Halo 5 is currently the main focus of the Halo franchise right now, there are still a decent amount of people who play Halo 4 everyday. There are many people who enjoy challenges being in the game and would like to see them brought back. There is also a community of achievement hunters, (xboxachievements.com and trueachievements.com) who would like them brought back so that the "The Challenged" and "Challenger" achievements would both be obtainable once again. Some people go for all the achievements in every Halo title, and again with these two being unobtainable that's no longer possible. Please 343i and Halo, we're just asking you to bring back challenges so there's another factor that keeps us playing your games and so we can 100% complete this game. No one likes seeing features go down, and fixing this would show your support for your past titles, and that you're not just abandoning them.