Rollback
also: roll back, rolled back, rolling back, rollbacks
Switching your live app back to the last version that worked, after a new deployment causes problems.
Restoring a system to a previous known-good state, usually by redeploying the prior release. Code rollbacks are often quick. Database changes are harder, because data written since the release may not fit the old version.
A new store layout confuses every customer on opening day. That night, you put the shelves back where they were, then plan the redesign calmly.
When a release breaks things for users, rolling back often stops the damage in minutes. Fixing forward under pressure can take hours and cause new bugs.
Error rates jumped right after the 3:10pm deploy. I recommend rolling back to the previous release first, then investigating the cause on staging.
Before we deploy this, tell me exactly how we'd roll back if it breaks, and whether the database change can be rolled back too.
Assuming a rollback undoes everything. It restores the code, but data created or changed since the release usually stays, and may not fit the old code.