It seems nobody really tested 11 to 13, or maybe any kind of major-version-skipping and you won’t find direct experiences here.
Your best bet is to follow the official procedure, so 11 -> 12 -> 13. I’ll leave you with the official upgrade guide for 11 to 12 and 12 to 13.
It seems longer than it is, as not every step is actually required for every system. When upgrading VMs, a snapshot pre-upgrade can also help you skip backup-steps in the guides.
It seems nobody really tested 11 to 13, or maybe any kind of major-version-skipping and you won’t find direct experiences here.
Your best bet is to follow the official procedure, so 11 -> 12 -> 13. I’ll leave you with the official upgrade guide for 11 to 12 and 12 to 13.
It seems longer than it is, as not every step is actually required for every system. When upgrading VMs, a snapshot pre-upgrade can also help you skip backup-steps in the guides.