macrozheng

Oct 28, 2025 · Backend Development

Why Spring Boot 4.0 Dropped Undertow Support and What It Means for Your Projects

Spring Boot 4.0’s release removes support for the Undertow web container due to incompatibility with the new Servlet 6.1 baseline, prompting developers to migrate to other containers; this article examines the technical reasons, Servlet 6.1 enhancements, Jakarta EE 11 standards, and compatibility across major servers.