Swagger UI vs Undertow

Undertow's 2.4 line opened in May 2026 with a release that combines three CVE fixes with a backlog of feature requests, several of them years old judging by their issue numbers — in-flight request processing time tracking, comments in the predicate language, a configurable async context timeout replacing a hard-coded one, HTTP/2 GOAWAY connection management, a TLS protocol version exchange attribute, and a method to invalidate all cache paths. The two releases since have been small: a handful of Jiras in 2.4.1, and a 2.4.2 whose entire release note is the sentence that it was tagged.

The 2.4.0 pattern — a long-deferred feature backlog shipping in the same release as security fixes — suggests features move when a release has to happen anyway rather than on their own schedule. What did ship points at operational control: timeouts that were hard-coded becoming configurable, connection lifecycle handling for HTTP/2, and attributes exposing TLS and timing detail to whatever sits above the server. Enabling test runs on JDK 25 in 2.4.1 is the only forward-looking item in the two follow-up releases.

With three entries and one substantive release among them, there is little to extrapolate from; the JDK 25 test enablement is the one thread that implies more work, pointing at runtime compatibility rather than features as the near-term focus.