Yes... I've just updated Tidal on my Mac Pro and Master is now an option in settings.

I do not have any MQA enabled kit (yet) but did download some music from 2L and streamed the same title from Tidal. (for an undecoded comparison) and yes when playing the MQA emblem replaces Hi-Fi in the bottom right hand corner of the screen.

For those interested Enya's latest "Dark Sky Island" also appears to be MQA. Can anybody confirm if any of these light up the blue LED.

Just off to the Meridian shop to update my explorer (1)

861v8+ID41, DSP8000, DSP5200HC, DSP5200, HD621, Lumagen Radiance XD, Panasonic TH50VX100, Dune 3.0. All controlled via Philips Pronto 9600 & iPad 3. (Living room).
MS200, DSP320's speakers (Kitchen).
Roon server on i7 Sonictransport supplying the 861,MS200 and a couple of SB touch.
Explorer for my Mac Pro.