Microsoft recently announced new improvements coming to Calendar Sharing in office 365. The improvements are not for users of exchange on-premises.
The first improvement is that you can share your calendar from any Outlook application, and have the same permission options on all Outlook applications.
The second improvement is that you can easily accept shared calendar invitations from any Outlook application, and see those shared calendars on all of your devices. The table below shows the current state of our work to make it simple to accept a shared calendar invitation.
The third improvement is that you can view all of your shared calendars on any device or calendar application. If someone changes a shared calendar, all other people sharing the calendar will see the changes instantly. You’ll also notice performance improvements when viewing and editing shared calendars. Using a shared calendar will be as fast and reliable as managing your own calendar.
Shared calendars sync to all devices
When you share your calendar with people today, they will enjoy the improved shared calendar experience after accepting the invitation. However, if you shared your calendar with people before these changes were enabled, they won’t have these improvements automatically.
With instant syncing enabled, a shared calendar will reflect changes made by others immediately. Currently, not all types of shared calendars support instant syncing. The following sections cover the types of shared calendars and calendar applications that support instant syncing.
Which types of shared calendars support instant syncing?
Instant syncing is enabled only if both users are in the same Office 365 tenant, or if the calendar is shared by an Outlook.com user.
To use instant syncing, your shared calendar must be enabled for instant syncing, and your calendar application must be updated to take advantage of this feature.
If your shared calendar is enabled for instant syncing, and you’re viewing it on Outlook on the web, Outlook for iOS, or Outlook for Android, you have the new sync experience. If you’re viewing that same calendar on Outlook for Windows or Outlook for Mac, you still have the old sync experience. Currently, for the same shared calendar, changes might appear faster in Outlook on the web, iOS, or Android than on Outlook for Windows or Outlook for Mac.
Summary of differences
The improvements are only rolling out for calendars shared between users in Exchange Online There are no changes to shared calendars when one of the users is hosted in Exchange On-Premises.
|Attribute||Old model||New model|
|How the shared calendar is stored||An entry (similar to a hyperlink) is stored in the recipient’s mailbox. The entry points to the owner’s mailbox but doesn’t store any calendar data in the recipient’s mailbox.||A new calendar is created in the recipient’s mailbox, and this calendar contains a copy of the owner’s calendar (starting one year prior to date of acceptance).|
|How recipient accesses the shared calendar||Reads and writes directly from the owner’s mailbox.||Reads and writes from the local copy of the shared calendar stored in the recipient’s own mailbox.|
|How the shared calendar syncs changes||The application periodically polls the owner’s mailbox for changes and syncs them down.||The service instantly syncs changes to the recipient’s local copy. This triggers a push notification to the application which syncs down the changes instantly.|
|Which applications the recipient can use to access the shared calendar||· Outlook for Windows
· Outlook for Mac
· Outlook on the web
|· Outlook for Windows
· Outlook for Mac
· Outlook on the web
· Outlook for iOS
· Outlook for Android
· Calendar for Windows 10
· All REST & EAS applications
Is my shared calendar on the old model or the new model?
Users that accept a new shared calendar invitation from Outlook on the web, iOS, or Android will automatically start using the new model of calendar sharing.
The easiest way to check if you have the improvements (meaning you’re on the new model of calendar sharing) is to check if the shared calendar appears on your mobile phone. If it does, the shared calendar is already upgraded to the new model.
How do I upgrade an existing shared calendar to the new model?
If you want your shared calendars to benefit from these improvements, you just need to recreate the shared calendar by doing the following:
- Ask the owner to re-share the calendar to you. They can do this from any Outlook application, even Outlook for iOS or Android!
- Accept the shared calendar invitation using Outlook on the web, iOS, or Android. It’s important that you accept the invitation from Outlook on the web, iOS, or Android. If you accept the invitation using Outlook for Windows or Outlook for Mac, the shared calendar will not be enabled with these improvements. You don’t need to remove any existing shared calendars before re-accepting.
You can accept shared calendars in one of two ways:
- Receive a sharing invitation via email and click the Accept button.
To add a shared calendar via the new model, you must accept the email invitation from Outlook on the web, iOS, or Android. Accepting from Outlook for Windows or Outlook for Mac won’t upgrade the calendar to the new model.
- Open the calendar by searching the directory for the calendar owner. Opening a shared calendar from the directory or address book will add the calendar via the old model of sharing.
In the future, shared calendars will upgraded to the new model regardless of which method you choose.
Sharing within the same tenant
There are three ways that a user can be granted access to a shared calendar:
- Direct permissions: The calendar owner shared directly to the recipient, and the recipient is listed individually in the calendar owner’s permissions list.
- Group permissions: The calendar owner shared the calendar to a security group, of which the recipient is a member.
- Default permissions: The calendar owner set a default permission for users in the same organization, and the recipient has access via the default permission.
Currently, instant syncing is only enabled for direct permissions and for group permissions if the group size is under 100. In the future, instant syncing will be enabled for all three of the above permission types.
Sharing outside a tenant
We do not yet support instant syncing for sharing outside your tenant. While you can share in these configurations, syncing will happen periodically. There are two types of cross-tenant sharing:
- Office 365 to another Office 365 user (if external sharing is enabled)
- Office 365 to an Outlook.com user. If external sharing is disabled, sharing to another Office 365 user also falls into this group.
For option 1, a full shared calendar is created, but the sync will happen approximately every 3 hours. Instant syncing will eventually be enabled for this setup.
For option 2, an ICS URL is generated when sharing, which the recipient can use to add to any calendar service. With an ICS subscription, the recipient’s calendar service chooses when to sync the ICS subscription to receive new updates. If the recipient is an Outlook.com or an Office 365 user, the sync will happen approximately every 3 hours.