Edit: finally found the box for my old unit and have my answer (I think). The new unit is V1.2, old one V1.0.
Thanks very much iFi, my replacement Hip-Dac arrived yesterday. Very happy with service I've received so far!
I've used it today, and it's prompted a couple of questions to throw out there:-
1) Volume difference. This new DAC is noticeably louder at a given volume. For example, with my Fiio FH5 plugged in I could previously have the volume somewhere around 11 o'clock with Powermatch turned on.
The new one will absolutely blow my head off if I do that. Volume is roughly equivalent at the same position with Powermatch off.
Anybody with 2 Hip-Dacs notice a volume disparity between them or have I uncovered a previously unknown fault with the older unit? Just to be clear, Powermatch works on both units and makes a clear difference, and I never felt the old unit lacked anything in this regard (though I had no frame of reference).
2) sound feels more 'impactful' with the replacement (though I wonder if this more a product of the above observation)
3) the LED that shows signal type, bit rate etc. The colours are different. The old one was a darkish purple for MQA, the new one is a Pink/Magenta colour (as per manual). Yellow is also far better defined, the old one it was almost greeny/yellow. Again, anybody with 2 units found a similar difference?
Battery life certainly seems better, got just under 6hrs off the first use.