The images below were added into the game via a data update which happened around 40 minutes before daily/weekly reset on 30 Dec 2019. Note that these content may take weeks if not months before being released into the game. Datamines only provide a preview of what is to come — I personally do not know when these content will be added into the game.
Basically, we are getting a bunch of events (summer, new years, roulette and more), 100 FREE pulls, summer + winter banner and orochi banner.
Datamines from before 30 Dec
Bonus: Upcoming Characters
If you check out the official King of Fighters ALLSTAR website, there’s a list of characters there. Turns out there are quite a few currently unreleased characters on the official site so based on this we can predict the upcoming characters in the near future. It seems like Orochi, Leona, Wolfgang Krauser and Eiji Kisaragi will be released in the game in the near future. Wolfgang Krauser and Eiji Kisaragi are predicted to be obtainable by purchasing their tokens in arena shop and then crafting them.