They were done adding new, unannounced content and features a long time ago. The only additions in the last year have been the long awaited course maker and VGT cars, and even they got very sparse.
Correct me if I'm wrong but the last previously unknown car or track was the Nissan LMP in June 2015, and the last new feature was I think paintable wings? A year ago?
I agree with the others that the only updates you're likely to see now are urgent bug fixes and then the update that removes online, whenever that may come. Certainly no big Spec 2.0 update full of new features is coming as some were certain was going to happen.