# Backward compatibility

OpenLoam is pre-1.0 and marked a prototype, but it already keeps a written
inventory of its **frozen public surfaces** — the things an app or an agent
builds against that OpenLoam promises not to break without a major-version bump
and a migration path. Everything not on that list is an internal detail and
may change in a minor release.

The full contract lives at
[`BACKWARD_COMPATIBILITY.md`](https://github.com/DeliveristsIO/open-loam/blob/main/BACKWARD_COMPATIBILITY.md)
in the repo root. It covers, section by section: tenancy (`OpenLoam::TenantRecord`,
`OpenLoam.tenant!`, `OpenLoam.as_tenant`), domain events (naming, publish/subscribe
signatures), the generators as the one interface, authorization (`OpenLoam::Policy`),
encryption at rest (the `v1:`/`v2:` ciphertext format), inbound/outbound
webhooks, the JSON API, custom fields, audit & undo, and a set of other keyed
surfaces (overrides, feature flags, and similar registries) — plus what
"frozen" actually means (shape is stable; adding an optional parameter or a
new value to an open set is fine, renaming or tightening semantics is not) and
the process for changing a frozen contract when it's unavoidable.

## Related pages

- [Configuration](/open-loam/reference/configuration/)
- [Pillar implementation reference](/open-loam/reference/pillars/)

Backward compatibility

OpenLoam is pre-1.0 and marked a prototype, but it already keeps a written inventory of its frozen public surfaces — the things an app or an agent builds against that OpenLoam promises not to break without a major-version bump and a migration path. Everything not on that list is an internal detail and may change in a minor release.

The full contract lives at BACKWARD_COMPATIBILITY.md in the repo root. It covers, section by section: tenancy (OpenLoam::TenantRecord, OpenLoam.tenant!, OpenLoam.as_tenant), domain events (naming, publish/subscribe signatures), the generators as the one interface, authorization (OpenLoam::Policy), encryption at rest (the v1:/v2: ciphertext format), inbound/outbound webhooks, the JSON API, custom fields, audit & undo, and a set of other keyed surfaces (overrides, feature flags, and similar registries) — plus what “frozen” actually means (shape is stable; adding an optional parameter or a new value to an open set is fine, renaming or tightening semantics is not) and the process for changing a frozen contract when it’s unavoidable.