We've upgraded to Unity 5.6 and have a bunch of problems to work out. We're seeing decreased performance for a lot of people (down 25% for a lot of people). Stuttering. A bunch of UI bugs due to a way canvases work in 5.6 now (which we're not sure is on purpose). Some graphical bugs. Models vanishing.
The new AI is completely untested too - so we've found a bunch of stuff we want to fix before we release it properly. We'll take the extra week to do this.
So right now our decision is to spend an extra week on this, instead of giving you a week of bugs before we fix them.
Yes, we will. I know it's kind of stupid and counter-intuitive, but the majority of people want it and I don't think we've given enough warning that the patch wasn't happening, so we are going to wipe officials at 3PM GMT.