Spring Boot 3 was released. It's time to upgrade to Spring Boot 3.

Before upgrading to Spring Boot 3, you should upgrade to latest Spring Boot 2.7.x version. If your app is using a version lower than 2.7.x, you should upgrade to next minor version first. For example, if the app is using 2.5.x, then upgrade to 2.6.x first, and then upgrade to 2.7.x.

When the app is upgrade to 2.7.x, we can use Spring Boot Migrator to migrate the app to Spring Boot 3. You can download the latest 0.13.0 version from GitHub. Spring Boot Migrator is written in Java and can run as a JAR file.

After starting Spring Boot Migrator, you can see the main UI.

Run the scan command (or s for short) with the path of Spring Boot project scan for upgrade recipes.

Run the apply command (or a for short) with recipe name to apply it. For upgrading from Spring Boot 2.7 to Spring Boot 3, use the recipe boot-2.7-3.0-dependency-version-update.

After applying the recipe, your Spring Boot app should be upgraded. Run all tests and fix any remaining issues.