A rollback is a way to return an app or service to an earlier version after a change causes trouble. It is like undoing a recent arrangement so a room goes back to a setup that worked.
If a new website update prevents people from signing in, a team may roll back to the previous version while it investigates. This can restore the earlier behavior more quickly than fixing the new version immediately.
Rollback plans should consider saved information too: restoring app files may not automatically undo changes made to a database.