We've made major updates to the way Outlook for Windows connects to and updates shared calendars. These improvements are available to all Outlook 365 customers that are using the latest Monthly Enterprise Channel, Current Channel, or Semi-Annual Enterprise Channel.

Note: The updated Calendar sharing functionality will continue to receive incremental updates and fixes. Current Channel and Monthly Enterprise Channel are the first channels to include these updates. It takes longer for these updates to reach the Semi-Annual Enterprise Channel. Therefore, we strongly recommend that users sharing and opening shared calendars switch to either Current Channel or Monthly Enterprise Channel.

This article describes the long-awaited improvements, along with other changes to form and function. To make sure you benefit from the improved experience, first confirm that you have the improvements enabled as described here.

Note: Shared Calendar improvements are now enabled by default in the most recent versions of Outlook, in all update channels for Microsoft 365 Apps. The Semi-Annual Enterprise Channel was the final update channel to enable the Shared calendar improvements by default (in version 2202, released on July 12, 2022).

Long awaited improvements

Instant sync and view of shared calendars

Previously, if changes were made to a shared calendar, it could take up to a few minutes for the shared calendar recipient to see those same changes reflected in their view of the shared calendar. Now, changes sync and appear instantly.

Similarly, when you select a shared calendar, it used to take up to a few seconds for the calendar to load. Now, the calendar is always pre-loaded and you will see the calendar instantly appear upon selection.

Editing series end date will not reset the past

  1. Select the event.

  2. Select The entire series, and then OK.

  3. Select Edit Recurrence and make your changes.

  4. Extend or end a meeting series by changing the series end date

    Meeting details in the past won't change and you won't see the message: If you changed specific appointments in the series, your changes will be discarded and those appointments will match the series again.

Accept a meeting without having to send a response

If you select Accept > Do Not Send a Response, others can still see your response in the Tracking tab. Previously, the organizer would not see your response if you did not explicitly send a response email. This improvement also applies if you chose not to send a response if you Tentatively Accept or if you Decline.

No prompt about who to send an update to

If you edit a meeting or a meeting series, and you only changed the list of attendees, you won't need to choose whether to Send updates only to added or deleted attendees or Send updates to all attendees. Outlook figures it out for you and will only send to added or deleted attendees.

Note that if the meeting contains a group or a distribution list and at least one attendee was removed, then the meeting update will be resent to those groups and lists to ensure that no users in the group are removed from the meeting.

Small changes in form and function

Last Modified By is no longer shown in the meeting item

Previously, users would see “Last modified by” in the bottom right of the meeting item. This value hasn't always been accurate for shared calendars so we've removed it. This is a pre-existing issue which is not specific to the latest shared calendar updates. We're re-evaluating this feature and may reintroduce it in the future. 

Can no longer add same calendar multiple times

Previously, it was possible to add the same shared calendar multiple times by adding it to different calendar groups. This is no longer supported. If you try to add a shared calendar which has already been added, it will not be added.

See the next section for details on selection behavior for shared calendars which were previously added multiple times.

Duplicate calendars will simultaneously select

If you have multiple entries for the same shared calendar, the selection state will be shared across those calendars. In other words, selecting any one of the duplicate calendars will select all entries for that shared calendar.

Cannot add attachments when responding to a meeting invitation

You can select Accept to accept an invitation, or select Respond > Forward to forward an invitation, but you can't add any new attachments to the meeting response.

Event drafts do not auto-save

Select Save to manually save a meeting or event draft. To resume editing later, select and open the draft from the shared calendar. You'll see the message You haven't sent this meeting invitation yet at the top.

No draft support for meeting updates

When editing a meeting that has already been sent,

  • If you save your changes, you will be prompted to save changes and send an update or continue editing without saving.

  • If you close the draft without saving, you will be prompted to save changes and send an update or close the meeting without sending an update. Changes will be discarded if you choose the second option.

Download shared folders setting is ignored

One of the past recommendations to address shared calendar issues was to uncheck the “Download shared folders” option. This mitigation is no longer needed with the improvements, and the state of this setting is ignored for any shared calendar that has been upgraded to the new sharing platform, when using an Outlook for Windows client with shared calendar improvements enabled.

Delay delivery rule will not apply

In Outlook for Windows, users can setup a rule to delay delivery of outgoing mail by a certain number of minutes. Previously, the invitation message to attendees would be delayed, but the meeting invite would still be added to the owner's calendar. Cancelling the meeting invite message being held in the Outbox did not cancel or remove the associated meeting from the owner's calendar. This discrepancy has caused confusion, and we have decided to remove this functionality in this update. When the improvements are enabled, outgoing meeting invites are sent immediately for updated calendars, and rules to delay delivery will only apply to outgoing emails and to outgoing invites for not-yet-updated calendars.

Custom forms support

All custom forms must be published to an Organizational form library. Custom forms published to personal form libraries are not supported.

Automatic accept or decline 

Previously, it was possible to enable a setting to automatically accept or decline meeting requests. This setting is not supported with shared calendar improvements enabled.

Want more?

Outlook calendar sharing updates

Outlook for Windows training

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Office Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!