Manage guest access for Groups using allow/deny block lists is a new Office 365 feature. We’ll begin rolling this feature out in the next few days.
This message is associated with Office 365 Roadmap ID 18546.
While our goal is to ensure that we notify you in advance of upcoming changes, we acknowledge that we did not provide timely notice for this change. We’ll continue to look for ways to improve our notifications.
How does this affect me?
You’ll be able to set-up a list of specific domains using a PowerShell script to allow or block guest access. For example: Block guests with emails from gmail.com or allow guests from contoso.com.
We’ll begin rolling this out today, and the rollout will be completed in the next two weeks.
What do I need to do to prepare for this change?
Please click Additional Information to learn more.