Just got a used copy in house. Tried out with minidlna (UPnp server) and works ok with Matrix Audio app.
Tried using BubbleUPnP app, this also worked ok.
Is there a way to "factory reset" the Mini-i 4 in the Matrix Audio app?
UPDATE!!
MA app cannot play gapless, and it does not sort tracklist correct. I have only tested UPnP (minidlna). The app also claims to have an update, but appstore (iOS) does not have any updates.
My recommendation is to use BubbleUPnP app, the it lists as should, and it plays gapless.
I also found the "load default" -> reset......, so my question is answered ;-)