My C4 is running 19.5 Matrix and hasn’t updated itself to 20. Can it run 20? If so, how do I update to 20 or do I have to do a full re-install with 20?
You have to update manually, it doesn’t auto.update between major versions. Make a backup of your install and try to update directly (this is not supported). If everything goes ok, fine, if it doesn’t it’s better to start from scratch on a new install.