However, as covered in this Microsoft Support article, when using a hybrid setup between Exchange on-premises and Exchange Online, Office 365 Groups won’t show in Outlook when the email address of the group is anything but (with ‘contoso’ being your Office 365 tenant name). The user doesn’t have to do anything, they just show up. Normally, any Office 365 Group a user is a member of, will show at the bottom of their mailbox folders under a section called ‘Groups’. Take a look at the Outlook contacts API reference.If you’re running Exchange in hybrid mode, there’s a big gotcha with Office 365 Groups and the ability to display them in Outlook 2016.
The API does not support accessing in-place archive mailboxes, not on Exchange Online nor on Exchange Server. The data can be calendar, mail, or personal contacts stored in a mailbox in the cloud on Exchange Online as part of Microsoft 365, or on Exchange on-premises in a hybrid deployment. The Microsoft Graph API supports accessing data in users' primary mailboxes and in shared mailboxes. You can extend app storage in a contact instance as an open extension, or add strongly typed custom data to the contact schema as a schema extension.You can keep the app local store synchronized by subscribing to change notifications and tracking changes to contacts and contact folders.This eliminates the overhead in converting between contact and user profile photos. The contact entity supports a contact photo which is implemented as the same profilePhoto entity as a user photo stored in Exchange Online or Azure Active Directory.Take advantage of other shared features and conveniences in Microsoft Graph Take advantage of this additional intelligence in people picker scenarios. As part of Microsoft Graph, you can also use the people API that looks at a user's Outlook contacts, as well as social networks, organization directory, and people from recent communication, and return information about people from all these sources that are most relevant to the user. You can use the typical CRUD operations for an Outlook contact to create and manage contacts. Leverage people API in Microsoft Graph to make better use of all people data For example, if Garth has shared a contact folder with John, or if Garth has delegated access to John, then delegated permissions from John would give you read access to Garth's shared calendar and contents as well. The contacts API lets you get contact items of the signed-in user, or of the users who have shared or delegated their contacts to the signed-in user. (Flagging is currently in preview in Microsoft Graph.) You can set a flag on a contact for follow-up.In addition, you can define a user's master list of categories, which can open up additional creative scenarios.
The contacts API lets you assign categories contacts, as well as events, messages, tasks, and group posts in a consistent way to enhance organization and discovery.Similarly to the customer experience, you can create contact instances and assign them to contactFolder objects.The contacts API lets you keep your customers organized, in close parity as the customers do it themselves through Outlook: For developers, tapping into the rich functionality of mail or calendar means opening up richer scenarios with the user's contacts data. Contacts provide a complementary function for messaging and calendaring by letting customers maintain a convenient, integrated store of contacts data within Outlook. Hundreds of millions of consumers and tens of millions of organization customers choose Outlook as their email client. Why integrate with Outlook personal contacts? Complement messaging and calendaring scenarios for hundreds of millions of customers Through Outlook, you can manage emails, schedule meetings, find information about users in an organization, initiate online conversations, share files, and collaborate in groups. Outlook contacts lets you store personal contacts' data, and is part of the Outlook messaging hub in Microsoft 365.