Release version 1606 of System Center Configuration Manager Current Branch contains many changes intended to both prevent issues and improve features. For the list of issues that are fixed, please see the Knowledge Base article below.
3184080 - Summary of changes in System Center Configuration Manager current branch, version 1606 (https://support.microsoft.com/en-us/kb/3184080)
Note that this list is not inclusive of all changes, but instead captures the work that our product development team believes is most relevant to our broad customer base. Many of these changes are the result of direct customer feedback on product issues, and ideas for product improvement. Version 1606 is available as an in-console update to be installed at the top-most site in a hierarchy. For more information, see the Checklist for installing update 1606 for System Center Configuration Manager.
J.C. Hornbeck, Solution Asset PM
Microsoft Enterprise Cloud Group