The Apache Commons HTTP Client 3 API library has reached its end of life. The Jenkins project still has a few plugins that depend on the API plugin that provides that library. The SAML Single Sign On (SSO) is the most recently released of those plugins.

Please replace your use of the Apache Commons HTTP Client 3 API library and the Apache Commons HTTP Client 3 API plugin.

We intend to deprecate the Apache Commons HTTP Client 3 API plugin in the future. If you don't replace your use and remove the dependency, users of your plugin will see a warning message in the Jenkins plugin manager that they are using a deprecated plugin. They won't be able to remove the deprecated plugin because it is a dependency of your plugin.