Spring Boot 2.x line. All new capabilities are opt-in or behaviour-compatible; the public API is unchanged. Highlights: retry-with-failover, per-instance circuit breaker, concurrency limit, body-size cap, active health probing, graceful drain, trace passthrough, control-plane token auth, built-in metrics + /trouve/manager/* endpoints, spring-boot-starter auto-configuration. Core fixes: thread-safe Matcher, fail-open health-check fix, retry fix, 502/504 on forward failure, exception boundary, Timer→ScheduledExecutorService, Redis cluster-mode RCE codec fix. See CHANGELOG.md (incl. Redis codec wire-format migration note).