There is another factor about this latest upgrade, which is very impressive to me.
For a long time, I had reformatted my SD card, using the largest byte size, as explained here...
The biggest and only drawback, which made me want to revert, was an occasional hiccup/delay when playing music. I have been very much procrastinating to redo my SD card, because I don't want to loose the fidelity I gained from this large byte size.
So the dx300 had these occasional hiccups, and then the dx320.
What I noticed is that the OG firmware had less hiccups than the other firmwares, BUT this latest firmware has had no hiccups at all playing all into the night not one time did it have any difficulty with my SD card at maximum byte size!
So I am very impressed at the performance this unit is showing now.
I have been only using Mango, as I like it's grander presentation over players like Neutron. Also it ran cooler on mangoOS. So far this OS is sounding the best I heard, having qualities reminding me of the best DAPs I heard. No regrets here. End game with the flexibility of amp boards...