The patch notes for 0.11.3 are here. It's a small patch compared to 0.11.4, but contains some useful changes such as the new chat improvements. We're expecting to deploy it at 10am tomorrow (NZ time).
Part of the reason for wanting to deploy the patch at the start of a workday is that we need to spend some time balancing the population levels of global and trade chat channels under the new system. It's hard to know in advance what channel populations will feel right for an appropriate level of chat traffic. For this reason, we'll be keeping a close eye on chat levels after deployment so that we can make sure that it isn't too slow or fast. (The technical explanation behind why we don't know how many people to put in each chat channel are that in the old system, people who have chat hidden are still in the channel. In the new system, they're not. We don't know exactly how many people had chat hidden because it was a clientside setting.)
I should stress that many of the changes planned for patch 0.11.3 have been included in patch 0.11.4 for technical reasons. 0.11.4 is a pretty big patch (over a gigabyte in size, possibly). My favourite part of it is the performance improvements. We've cut over 10% off the size of the game.