MS 365 Outlook - Disable or hide "New" Outlook button

How to HIDE the “Try the new Outlook” toggle displayed in Outlook:
  1. Registry File:
Windows Registry Editor Version 5.00
  1. Office Group Policy (Administrative Template files must be downloaded and installed):
User Configuration > Administrative Templates > Microsoft Outlook 2016 > Outlook Options > Other: Hide the “Try the new Outlook” toggle in Outlook