The resilience4j-bom in version 2.4.0 does not contain a reference to resilience4j-spring-boot2. Version 2.3.0 contained one. I couldn't find instructions in the release notes announcing the end of resilience4j-spring-boot2. The module and its source code are still present in master branch.

I could trace that issue to commit a664c7a dropping the module while upgrading to Java 21. Dropping Spring Boot 2 support seems natural when upgrading to a Java 21 baseline as Spring Boot 2.x does not support Java 21.

There is a discussion in the issue #2224 that this change might require a new major release but the change made it into 2.4.0. The decision to update to JDK 21 was later reverted in #2415 but without re-adding the resilience4j-spring-boot2 module to resilience4j-bom .

I think the change #2331 should be checked if there are other changes that need to be reverted. Modules removed from resilience4j-bom are:

• resilience4j-spring
• resilience4j-spring-boot2
• resilience4j-spring-cloud2

I can't tell if the changes in libraries.gradle are important but gradle/libs.versions.toml doesn't contain references to Spring Boot 2 either.

As we are already on Spring Boot 3, I realized that I need to replace the dependency on resilience4j-spring-boot2 with resilience4j-spring-boot3 in my project. This will also solve this issue for me but others might still be at Spring Boot 2.