# Unversioned Breaking Change

> A defect in which a public contract changes incompatibly without a version, a deprecation path or a compatibility test.

Record: `architecture:unversioned-breaking-change`
Kind: anti-pattern
Layer: [Enforcement Core](https://banes-lab.com/records/layer/enforcement-core.md)
Severity: discouraged
Scope: contract_compatibility, event_messaging, architecture_evolution
Canonical: https://banes-lab.com/ontology#architecture-unversioned-breaking-change

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Unobservable Failure](https://banes-lab.com/records/architecture/unobservable-failure.md) and before [Distributed Monolith](https://banes-lab.com/records/architecture/distributed-monolith.md).

## Repair

- Refactored by: bump_version, add_compatibility_adapter, deprecate_gradually, add_contract_tests, publish_migration_guide
- Detected by: API_diff_breaking, schema_field_removed, type_narrowed, event_semantics_changed, no_version_bump, no_deprecation_window
- Violated by: Change a public API, schema, event, protocol, behavior, or package contract incompatibly without version bump, deprecation path, compatibility test, or migration notice.
- Measured by: breaking diffs released without a version bump
- Enforced by: API and schema diff gates in the release pipeline

## Severity

- [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md)

## Category

- [Anti-patterns](https://banes-lab.com/records/architecture-category/anti-patterns.md)

## Force

- [Architecture evolution](https://banes-lab.com/records/force/architecture-evolution.md)
- [Contract compatibility](https://banes-lab.com/records/force/contract-compatibility.md)
- [Event messaging](https://banes-lab.com/records/force/event-messaging.md)

## Negated by

- [Consumer-Driven Contracts](https://banes-lab.com/records/architecture/consumer-driven-contracts.md)

## Linked from

- [Seven controls, seven classes](https://banes-lab.com/software-architecture/decay/seven-controls-seven-classes.md)
- [Anti-patterns](https://banes-lab.com/ontology/principles/architecture-category-anti-patterns.md)
- [Contracts / Interfaces / Compatibility](https://banes-lab.com/ontology/principles/architecture-category-contracts-interfaces-compatibility.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The forces](https://banes-lab.com/ontology/schema/the-forces.md)