Spring Boot 4.0.0 Release Notes

Upgrading from Spring Boot 3.5

Migration Guide

To help with upgrading, a migration guide is available.

New and Noteworthy

Tip	Check the configuration changelog for a complete overview of the changes in configuration.

Dependency Upgrades

Spring Boot 4.0 moves to new versions of several Spring projects:

• Micrometer 1.16.0

• Micrometer Tracing 1.6.0

• Reactor Bom 2025.0.0

Numerous third-party dependencies have also been updated, some of the more noteworthy of which are the following:

• Elasticsearch Client 9.2

Miscellaneous

Apart from the changes listed above, there have also been lots of minor tweaks and improvements including:

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Deprecations in Spring Boot 4.0.0-RC2

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