Just a quick note. You may miss several SCCM branches and are still on version 1602 or 1606 of SCCM. Despite stated by Microsoft direct upgrade from Branch 1602 to 1706 is not possible. The maximum version you can upgrade from Branch 1602 is 1702 (even though you can see versions 1706 and above in the manifest file). So the actual upgrade would be three steps process: from 1602 to 1702, download 1706 and from 1702 to 1706. Same applies to the branch 1606.

Keep this in mind when planning for SCCM upgrade.