What spring-projects/spring-boot shipped
Written by FoxPlug from public releases; not affiliated with Spring. An automatic summary of the public release, pull request and commit data of github.com/spring-projects/spring-boot. Spring did not write it and does not use or endorse FoxPlug. Every line links to the public change it describes.
Get a weekly update like this for your product, free
Week of September 21, 2026
What shipped
- Spring Boot 4.2.0-M2 released with deprecation of AppOptics, performance improvements for classpath entry lookup during jar creation and extraction, and new Kafka listener configuration options. Release
- Spring Boot 4.2.0-M1 released with refined Forwarded headers configuration for Jetty servers, disabled Micrometer global registry in tests by default, graceful shutdown improvements for Jetty, and deprecation of RestTemplate support. Release
- Properties migrator can now fail application startup when configuration keys requiring migration are found via the new
spring.tools.properties-migrator.fail-onproperty. Pull request #51855 - Default Cloud Native Buildpack builder switched from Ubuntu Noble to Ubuntu Resolute, the latest Ubuntu LTS release. Pull request #51249
- Nullability checking enabled for tests in the spring-boot-jersey module, resolving 8 NullAway errors in the process. Pull request #51861
Why it matters
Two milestone releases bring deprecation notices for AppOptics and RestTemplate alongside performance and configuration improvements. The properties migrator enhancement helps teams catch configuration issues during startup, while buildpack and test quality improvements address operational and development concerns.
Changelog entry
- Deprecate AppOptics as it has retired Release
- Improve classpath entry lookup performance during jar creation and extraction Release
- Add spring.kafka.listener.await-async-results-on-stop property Release
- Rationalize Kafka configuration outside of KafkaProperties Release
- Refine Forwarded headers configuration for Jetty servers Release
- Disable Micrometer global registry in tests by default Release
- Use GracefulHandler rather than StatisticsHandler to coordinate graceful shutdown of Jetty Release
- Deprecate RestTemplate support Release
- Add spring.tools.properties-migrator.fail-on property to allow properties migrator to prevent application startup Pull request #51855
- Switch to ubuntu-resolute-builder as the default Cloud Native Buildpack builder Pull request #51249
- Enable nullability checking for tests in spring-boot-jersey module Pull request #51861
Spring Boot 4.2.0-M2 is out with AppOptics deprecation, Kafka configuration refinements, and classpath lookup performance gains. M1 brought Jetty graceful shutdown improvements and RestTemplate deprecation.
Spring Boot 4.2.0-M2 is now available. This milestone includes deprecation of AppOptics support, performance improvements for jar creation and extraction, and new spring.kafka.listener.await-async-results-on-stop configuration. Earlier this week, M1 was released featuring refined Forwarded headers support for Jetty, disabled Micrometer global registry in tests by default, and RestTemplate deprecation notices for teams planning migrations.