My oldest (2008) computer just became free for 'experimentation'. After 12+ years of running Mint I decided to install Zorin Core. It all works as well as I had hoped; I'm a little surprised to find that the kernel level in use with Core 16 is 5.11, where as I was advised, just a few months ago, when using Mint on this computer, that I should be using kernel version 5.4 for such old hardware. is this not true for Zorin OS?
I also notice that multiple releases of a given version of the Linux kernel are not installed, as they are in Mint. Does Zorin automatically delete obsolete kernels? Can I indeed revert to an earlier kernel version?
This is harder to answer...
You probably could use the 4.15.0-75 kernel, even.
Newer kernels contain additional drivers for newer hardware, as the kernel development tries to keep up with Hardware releases.
Using a newer but stable and vetted kernel on older hardware should normally be fine.
Where people run into trouble is when they try installing the Newest Kernel for only the reason that it has a higher number, so they assume it must be good... and they install an Untested and unstable kernel. This can cause problems, especially on older hardware.
"Install Kernel x+1 because it must be better than my current Version x Kernel". Yep, that was me. But, having reverted Mint, under advice, from 5.11 to 5.4 and found a more stable system, I will no longer do this. However, having said that, the 'clean' Zorin Core 16 install seems to be running perfectly stably on kernel 5.11, so I can switch to a different principle: "If it ain't broke, don't fix it".
In the event it does break, your advice on how to revert is most clear - thank you.
4 series kernel is rock solid.