So there's an updated called 'the yappening' which seems to be focused on the grunts from Halo.
Multiplayer has had a massive update - not only does the loading screen show the map, it shows what game type, score to win and player tags.
On top of this they've doubled the packet data to and from servers, they originally ran to compliment 30fps but now they run to take in the new 60fps standard.
We’ve upgraded the rate at which network packets are sent by the server in Halo 2, Halo 3, Halo 4, and Halo 2A. We have also increased limits on how much data each individual packet can contain. This includes data about the position of bipeds, where they’re aiming, what projectiles they’re firing, etc. The server prioritizes what data is contained in a packet until it reaches a maximum size. In gaps where the client hasn’t received a certain type of information from the server (due to latency or prioritization), the client predicts what this information should be based on the last data received. It then corrects its predictions upon receiving new data. This can result in cases of “rubber-banding” where a biped’s position is predicted locally and then corrected by the server. By increasing the allowed size of packets as well as their frequency, we have significantly reduced these gaps. This results in less prediction and correction due to more frequent and more complete updates from the server. In Halo 3, the clients would send 15 packets per second to the server, while the server would send 30 packets per second to all clients. Now both servers and clients will be networking at 60 packets per second, aligning with the framerate.