Hello @sigsegv111
You can take a look at the, daily basis, development here:
https://github.com/Beep6581/RawTherapee/branches
As regards the GPU future development I suppose it will take a looong time before it will be available.
This being stated, I am NOT a developer and I will be very happy to be proven wrong 
Currently both darktable and vdkt support GPU processing as regards the open source RAWs processors often discussed on this forum.