Install the runtime selected by the SDK package. For a shared service, deploy compatible API and worker builds together. See release versions.
SQLite applications
The attachment-capable runtime upgrades supported schema 7/8 databases to 9. The application state lock prevents concurrent runtimes from opening the same state directory. Older binaries refuse schema 9. Keep a pre-upgrade backup if you need to restore the previous application; replacing the executable alone is not a database downgrade.
PostgreSQL services
Execution storage uses schema 7. Stop admission, drain workers and stop old API/SDK processes before the explicit migration. Allow execution leases to finish or expire; do not delete ownership records to force an upgrade. Use the migration command documented for your matching service build.
Old workers are fenced from writing the new schema. Do not change a schema marker manually to make them start. Restore a reviewed backup for rollback rather than rewriting runtime metadata.
Recording storage
Observability uses its own schema and connection. Run its explicit migration when using PostgreSQL recording, even if it shares the same PostgreSQL server as execution storage. Follow recording configuration.
Check after an upgrade
Resume a saved session, submit a follow-up, check tools/approvals and read any stored attachments. Verify recording/export health when enabled. Preserve the previous app package and backup until your application checks pass.