Here is the answer from Kay:
That's not "simple" for anyone, unless you're willing to accept possible issues with desynchronization (such as cloning items or "Jesus bug"). Even Cipsoft still uses complete rollbacks until today, when something goes down. So does Medivia, for example. If you actually followed our project, I even made posts about that months ago that IF something ever goes bad, for whatever reason, we WILL do a rollback to the last full save. It's the only reasonable way to handle it and I regret agreeing on all those "compensations" with adding exp etc. This shouldn't have happened.
People who stay are going to be compensated with extra premium days today.
So /save isn't an option for them, aswell as Helaxo said server needs to be restarted so there can't be often ss