… which we try to do for openHAB 2. But you should note that the CMD servlet has NEVER BEEN an official API, but just an internal servlet of the ClassicUI - and the official REST API of openHAB 2 is still compatible with openHAB 1.
Having said this, the Classic UI still has this servlet, only its url has changed to http://localhost:8080/classicui/CMD?<itemname>=<command>. So if you have this UI installed, you can still do similar things as before, but you should note that this is still no official API and never will be - because doing state changes through HTTP REST is completely against and RESTful concepts and a very bad design!