Oracle Enterprise Manager 13c Release 4 Update 4 (18.104.22.168), RU4 in short, is now available for download! You can download the Release Updates from My Oracle Support: Patches & Updates.
Release Updates (RUs) are a way for us to roll out new EM features and bug fixes more quickly, without waiting for a major release vehicle. Release Update patches are versioned with a trailing digit indicating the RU version (here, 22.214.171.124). Note that RUs are cumulative, which means that the most recent RU includes functionality from all previous release updates. It is our general recommendation that you apply the most current Release Updates as soon as possible.
For the complete article see the OEM blog post by Daniella Hansell