does cubase 8.5.3 support MPE
Depends what you mean by support. You can use MPE hardware and compatible 3rd party software with it fine, but the provided Cubase plugins aren’t MPE compatible, nor are Steinberg’s commercial VSTi’s. I’m hoping they’ll rectify this soon now Bitwig and Ableton have gone full MPE. They introduced explicit MPE support in C10, but 8.5.3 should work too, just as multichannel MIDI.