I'm sorry, but you misinterpreted the screenshots.
Please refer to my 1st line in my 1st post:
>>>>I had to freeze my device on Kernel 6.1.92 & Bullseye to remain operational. Now trying to update/upgrade to Kernel 6.6.nn <<<<
I was always on Bullseye since years now and Kernel 6.1.92 frozen since early this year. Trying to move from 6.1.92 to 6.6.42 (switching kernel after defreeze in armbian-config) created a mess including throwing me back onto Buster, God knows why and how!
May be, that I am using a code that is not supported on a hardware that is not supported, but normal Linux' way of upgrade should still work and for the time being, I am almost sure, that the upgrade doesn't work, because you guys haven't created the proper public key for apt.security to accept the upgrade.
RGDS
hk