OpenUpgrade migration overlays

openupgrade_overlays/ contains source-controlled, version-specific migration artifacts that supplement the normal OpenUpgrade script path.

The first directory level is the target Odoo series. For example, 18.0/ is prepended to the OpenUpgrade script path by scripts/migrate/migrate_14-18.sh during the final 17 to 18 upgrade. Paths below that level follow the OpenUpgrade module/version layout, such as website_sale/18.0.1.1/post-migration.py.

These files run as migration scripts in an OpenUpgrade context. They are not ordinary runtime addons, are not added to a production Odoo addons_path, and do not belong in templates/ or testkit/.

Overlay changes can mutate database schema or data during migration and must be version-specific and safe to rerun. Validate them only through an approved, disposable migration workflow that follows the canonical PMIVerse migration policy. Never test an overlay against a live production database.

See the 14 to 18 migration runbook for the consuming workflow. Generated Python bytecode and __pycache__/ directories are local artifacts and must not be committed.