I brought my test box up to 4.211.64-10 one step at a time and then ran the upgrade script to 5.211.65-1. When I rebooted I got an error message:
Kernel panic - not synching:VFS:Unable to mount root fs on unknown block (0,0)
I then went back and was able to bring the system up using kernel 18.104.22.1688.0.1.e16.i686 and then took a chance and ran yum kernel reinstall after which I rebooted and the system came up with kernel 22.214.171.1241.e16.i686.
As far as I can see everything is running normally. Am wondering if this was a once off glitch or if others might have experienced.
I ask because I have a system ready to go into production and don’t want to upgrade it to the latest track until I am sure all is well.