Most hi-end systems are analogue from the DAC output to the speakers and are IMHO the least threatened by MQA, which presumably will only require a new (or modified) DAC or outboard module.
Meridian systems on the other hand appear to present a very complex architecture and ironically are probably the most "threatened", i.e. they may need both h/w and s/w updates across multiple components.
All of which is moot until there is sufficient (good) music available to justify the modifications. It is, of course, the music which may have to be repurchased, rendering any existing investment obsolete, in MQA terms at least.