Upgrades & Migrations

Nucleus schedules upgrades for managed deployments. Self-hosted institutions choose their maintenance window and apply security fixes within the period in their agreement.

1. Review release notes, the supported upgrade path and dependency compatibility. Pin the approved image digests and verify their signatures before startup.
2. Rehearse in an approved test environment. Verify licence compatibility, migrations, reconciliation and recovery. Record the exact release, backup and sign-off owners.
3. At cutover, fence new writes and dispatch. Preserve evidence for in-flight instructions and callbacks, and take the approved consistent backup. Apply the release in the documented order.
4. Verify service health over trusted TLS, schema changes, ledger control totals, holds and pending transfers. Resume writes only after the required sign-off.

A Compose stop/start requires a maintenance window. If checks fail before new effects are accepted, keep writers fenced and use the approved rollback plan and exact verified backup. Once new effects exist, recover forward or use an approved reconciled rollback that preserves the new activity. Restoring a pre-upgrade snapshot after reopening can erase accepted banking activity.