It's not likely going to be a single update, those two features are made up of a lot of smaller, dependent bits and pieces. We're already working on the framework that the simulations will use.
The plan is to start with the base temperature simulation and then add on top of it to simulate more dynamics, such as the seasonal energy balance, and the influence of atmospheric composition.
It's hard to give any kind of estimate, other then it will take some time before we get to higher level stuff, like simulating the CO2 level of the atmosphere.