App config — Krizaka Java

krizaka-app-config — app version compatibility — a public app-config endpoint, 426 Upgrade Required and N-1 contracts, from database parameters.

<dependency>
  <groupId>com.krizaka</groupId>
  <artifactId>krizaka-spring-boot-starter-app-config</artifactId>
</dependency>

A mobile or desktop app outlives the API it calls. The app sends three headers on every request — X-Client-Platform, X-Client-Version, X-Contract-Version — and the service answers:

GET /api/v1/app-config?platform=ios&version=1.4.0, public and cached: the minimum and latest version, the update mode (none, soft, force), maintenance, the contract range, the store URL, feature flags and a localized message;
426 Upgrade Required (Problem Details carrying that payload) below the minimum, before authentication;
N-1 compatibility: the previous contract keeps working, with Deprecation: true and a Sunset date.

Every value is a database parameter with safety bounds, a reason and an audit trail; the admin API (krizaka.app-config.admin.enabled=true) publishes, lists the history and rolls back. If the parameters cannot be read the service serves the last known value, then permissive defaults: an outage of the parameters never locks the app.

krizaka:
  app-config:
    store: jdbc          # memory in tests
    cache-ttl: 30s
    admin:
      enabled: true      # needs ROLE_ADMIN (krizaka.app-config.admin.authority)

The tables are in krizaka-app-config-schema.sql (apply them with the service's own migration), and the contract is shared with the TypeScript package @krizaka/app-config: one JSON schema, one fixture, both implementations pass it.