CASAN/infra/production/UPGRADE_ROLLBACK.md

Upgrade and Rollback Runbook

The compatibility gate is mandatory before every deployment or rollback:

bash packages/casan-harness/scripts/bash/upgrade-compatibility.sh check \
  --from 1.0.0 --to 1.0.1

Only an explicit rule in compatibility-matrix.json can permit a version pair. Before rollout, verify provenance, create and verify a state backup, smoke the extracted artifact, deploy immutable image digests, and verify an Evidence Pack after deployment. A rollback requires the same gate with --rollback, plus an approved change record and a verified backup.

Do not infer compatibility from matching image tags, passing unit tests, or successful container startup. Add and review a new matrix entry before any cross-minor or cross-major migration.