Volumio CAN handle MQA, but only under some circumstances:
You need to have a USB DAC that is MQA hardware decoding compatible. For example, a Pro-Ject Pre Box S2 Digital can play any MQA file
Volume must be set at 100 or NONE (see PLAYBACK OPTIONS menu)
In any other condition, MQA will not work on Volumio. This is mainly because we can't incorporate the MQA software decoder into Volumio as we will violate MPD's GPL license.