As mentioned in the announcement last year, the Spring Boot 1.x line has reached end of life. Spring Boot 1.5.22 which was released earlier today will be the last release in the 1.x. line.
We expect most users to have upgraded their applications to Spring Boot 2.x. For those that haven’t migrated yet, we strongly advise doing so as soon as possible. There are detailed instructions on how to migrate from 1.x to 2.x in the migration guide. For a smooth upgrade experience, we recommend upgrading in phases instead of jumping straight to the latest stable release. Once the upgrade from the latest 1.5.x version to the latest 2.0.x version is complete, you should upgrade to the latest release in the 2.1.x line.