Today marks the day that Bungie passes the torch over to 343 industries and Bungie's last ever Halo matchmaking update.
Its a relatively small update on the surface, but there is stuff behind the scenes to get ready for the transition.
PLAYLISTS
General
* Removed Rebirth from all playlists
* Added community maps Chateau, Eden Minor and Renova to Team Slayer
Premium Battle
* All objective gametypes in Premium Battle now use the Big Team variants
* Removed Hot Potato from Premium Battle
Team Objective
* All gametyes in Team Objective now feature DMR/AR starts (excluding Classic and Pro variants)
* Integrated 3 Flag, 2 Flag Slayer and Speedflag into Team Objective
Grifball
* Updated with latest maps and gametypes from Grifballhub.com
MLG
* Removed MLG King on MLG Zealot
MAPS
Sword Base
* Soft kill added to small ledge
Zealot (not Arena Zealot)
* Soft kills added to specific locations in space
Boardwalk
* Both Sniper Rifles now spawn at 180s with 2 spare clips
Anchor 9 / Unanchored
* Rocket Launcher now spawns at 180s with 1 spare clip
Mt. Lam Lam
* Removed Camo powerup
GAMETYPES
General
* Slayer DMRs game variants now use the default vehicle set
* Big Team Assault gametypes now use 3 second arm time
[Source]
343 is indeed planning to continue to update the playlist, how often or when their first update is planned is unknown at this time. I expect the details of the Transition to be revealed soon.