The R2DA 100th Version Celebration is self-explanatory; it celebrates R2DA's 100th version. Something hardly achievable for the previous games of the line-up. Although not being an event, it did introduce special permanent features that otherwise wouldn't be around for another part of the year.
This is the second celebration of something in the R2D series that introduced permanent features, the first one being R2D's 8 Million Visits Mini-Event that introduced King Cake and the ability to spawn Cake on top of your head once a round, at will.
Informally known as the "Chronos Series".
This version contains the most amount of weapons released in a single update, those being the M249, Famas, RPG and Karambit.