SFGameZ64, yes, the classification described in the second blog post is that is accepted currently, maybe with minor changes (some numerical values and words for subclass names).
To update old mods, you have to change Class to one of the basic classes, and describe atmosphere and hydrosphere. SE will classify volatiles automatically (airless, arid, marine, oceanic etc.) It have hard-coded boundaries between lacustrine, marine, oceanic and superoceanic, based on hydrosphere depth (calculating surface area is not possible, so depth is used for now).
Selena -> Terra without atmosphere
Desert -> Terra with atmosphere, but without hydrosphere
Terra -> Terra with atmosphere and hydrosphere
IceWorld -> Aquaria with or without atmosphere, and without hydrosphere (well, "methanosphere"?)
Titan -> Aquaria with atmosphere and hydrosphere
Carbonia, Ferria - the same as Terra, but with different bulk composition (defining it is not mandatory though)
Neptune and Jupiter are not changed (IceGiant and GasGiant are also accepted).
Old class names Desert, Selena, IceWorld and Titan are also accepted, and converted to corresponding new classes. This is for backward compatibility. However, it doesn't work well in all cases.
Mass prefix (mini-, sub-, super-) is added automatically based on planet mass.