All characters that are right now stationed in empty systems should be moved away to original systems. Visiting these systems before we have 4.82 first beta is not advised if you are not absolutely sure that you'll have time to go back.
This does not apply to faction/clan systems or any systems that have bases. Only empty systems are subject for removal.
Most of new systems will be removed from next release, and if your character will stay there, the client and server will crash if you try to log in with that character.
So if you will see a character with '????' symbols where system name should be, DO NOT select it and contact admin so that your character will be safely moved. If you log in, your character will be lost, and game server & client will crash.