Sweet! That was all it took (removing those 2 "missing" files).
I see
[ OK ] DietPi-Patch | APT autopurge
[ OK ] DietPi-Update | Incremental patching to v6.31.2 completed
[ SUB2 ] DietPi-Update > Completed
[ INFO ] DietPi-Update | Current version : v6.31.2
[ INFO ] DietPi-Update | Latest version : v6.31.2
... and
[ OK ] DietPi-Patch | Everything done! Terminating the obsolete DietPi-Update parent instance...
Terminated
root@DietPi:~#
So, thanks for helping me update the little guy, now I want to watch the temperature - hopefully, it will stabilize below 70 C.
I can also ask Allo if they think it would be possible to use the "Powersave" CPU governor setting now - and would that still allow this device to act as a "Roon Bridge" - its intended use - or would CPU requirements of that functionality preclude low-power use.
And... it doesn't look promising on the temp - already @ 66 C, and we aren't doing anything [yet].
EDIT: temp still climbing (67 C), but I notice that now, when I attempt to use the Allo "dashboard" interface to shut down various of the audio servers (everything but Roon Bridge) that this no longer works right. I can disable individual services using the GUI, and tell it to save this new state, but it doesn't work - they are still shown as "running").
How this could be connected to the update not being able to include those 2 files isn't very clear... I will go back to the Allo support forum and bring things up to date there, as well as relaying your "Stretch" comments.