Definition
Rollback restores a previously known-good version of software, configuration, a model, a policy, or data after a failed or harmful change. It is a recovery action, not proof that every consequence has been undone.
A workable rollback plan identifies the recovery point, preserves compatible artifacts, records dependencies, and defines who can trigger the operation. It must cover more than code. Schema changes, model and tokenizer pairs, feature flags, prompts, policy versions, indexes, and credentials can all determine whether the old state still works.
External effects often need separate compensation. An application rollback cannot unsend an email, recover disclosed data, cancel a completed payment, or automatically reverse an incompatible database migration.
Distinguish it from nearby terms
Rollback returns controlled state to an earlier version. Retry repeats an operation. Roll-forward applies a new change that repairs the bad state. Compensation performs a new action intended to offset an external effect that cannot literally be reversed.
Check your understanding
A release is reverted successfully, but the new version already wrote records the old version cannot read. The code rollback worked while service recovery failed because the data path was not reversible.