All Outlook clients that use cached mode will download a new OAB after a move to vNext. This is an expected behavior and will automatically occur within 24 hours. The OAB check that's performed by the client happens at a random interval. Therefore, you may have to direct users to manually force an update if they experience the issue that’s outlined in this article.
To manually download the address book, follow these steps:
- Locate Send/Receive, and then select Send/Receive Groups.
- Select Download Address Book.
- Select Download all changes since last Send/Receive, and then select OK.