upgrade root server plan

Normally, no data is lost and the server does not have to be set up again.

A backup should be available in one way or another. Something can always go wrong.

You can only upgrade, not downgrade. If your new server has more SSD space, that additional space will not be added automatically. The easiest way is to boot the Gparted Live ISO in SCP and resize your partition(s) and then boot from drive again.

Always do backups!

If you upgrade to another generation you can only end your contract and start a new one. Backup / snapshot might help if your contracts overlap. Note that you might have to pay more if you want your prefered location (or bet on your luck). You can post on Swap Ownership / Offering if you cannot cancel your contract as early as you wish.