Computer Configuration > Administrative Templates > Microsoft Office 2016 (Machine) > Updates
Machine
HKLM\software\policies\microsoft\office\16.0\common\officeupdate
This policy setting prioritizes the use of Windows Background Interface Transfer Service (BITS) by the Office client when downloading Office updates from the Office Content Delivery Network (CDN). If enabled, BITS will be used on devices that are downloading Office updates directly from the Office CDN and throttle values used by BITS will be honored. The device will not leverage BITS if updates are obtained from a local UNC share. If disable or not configured, BITS will not be prioritized and http will be the primary transport for downloading updates. Note: This policy setting only applies to subscription versions of Office, such as Microsoft 365 Apps for enterprise, and to subscription versions of Project and Visio.