Update on the situation...
It was permission issue, setting up correct permissions after the upgrade solved the problem.
During my testing I've also found out that not setting sleep in rc.local will not trigger autostart, in my scenario "sleep 60" (seconds) was barely enough, so to make sure all other hardwarde is booted up (storage, switches etc) before booting up VM's, in my scenario 300 seconds is set.
I prefer using rc.local and setting up autostart via vApps because you can fine tune starting order of the apps and delay start for each.
In regards to colons vs equals:
If you go with colons, you can simply type whatever you want, eg. "xe pool-param-set uuid=<VM_UUID> other-config:whateverthefuype:true" -> you will not any prompt that command does not exist or similar. I am not sure if that's supposed to be like that?!
My problem here is resolved, maybe this will help someone in the future.
