Outlook is updating to automatically hide duplicate contacts, with rollouts starting late August 2024 and ending mid-October 2024. This affects Outlook on the web and new Outlook for Windows, while other versions will show all contacts. No admin action is needed, but users should be informed.
Applies to: Exchange Online · Microsoft 365 for the web · Microsoft 365 apps
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).