You could perhaps ask Hi Fi Berry about compatibility, but I know they needed to change drivers for the Pi5, so my guess the Pi4 (or Pi3) is a safer bet.
Given you have a Pi4 on hand, I’d be tempted to try it (uncased) and see if it works.
It it does it looks like Hi Fi Berry are still selling Pi4 cases.
Yep, I see that The Pi Hut do HiFiBerry cases for both the 4 and 5, both are £33.50
I can pick up a 5/1Gb for £43.20, and just use that for RoPieee / Roon.
That then means I have my 4B/4Gb, and a very nice PiMoroni purple heatsink case for it, for experimentation. It seems that the colour anodised cases are no longer available, which seems a shame.
Have to say, after not looking at Pi stuff for a while, that a 4B/4Gb is now £96, and the 5 ranges from £43.20 all the way to £292.80. The price of RAM seems to have made Pi pricing and availability rather nuts.
Cheers @GregD I think what I’ll do is run it with the Pi 4B/4Gb with the Digi+ hat bare first (have got it to the point that it is running RoPieee) so now to connect it to a DAC.
If that all works, I’ll probably grab another 4B, but maybe with 1Gb or 2Gb, as they are £33.60/£52.80, as well as the HiFiBerry case.
That should give me a few years use before the 4B is no longer supported.
@spockfish Yep, parked it in a box in storage for a while, so dragged it out and fired it up. Cheers for all your efforts.