Offline Support for Calendar - Create, Edit and Delete Event support
Services
Affected Platforms
Summary
Offline support in the new Outlook for Windows will allow users to create, edit, and delete single calendar events without internet. Rollout begins late September 2025, completing by mid-December. Recurring events offline are not supported. Controlled by the OWA mailbox policy setting OfflineEnabledWin.
Details
Updated September 4, 2025: We have updated the timeline. Thank you for your patience.
We’re expanding offline capabilities in the new Outlook for Windows. Users will soon be able to create, edit, and delete single calendar events even when not connected to the internet. This enhancement improves productivity and flexibility when working offline.
This change is associated with Microsoft 365 Roadmap ID: 490059
When this will happen:
Targeted Release: Rollout will begin in late September 2025 and is expected to complete by late October 2025.
General Availability (Worldwide): Rollout will begin in late October 2025 (previously mid-September) and is expected to complete by mid-December 2025 (previously mid-October).
How this will affect your organization:
Users with offline mode enabled in the new Outlook for Windows will be able to:
- Create new single calendar events while offline.
- Edit or delete existing calendar events that have been previously synchronized within the offline timeframe set in Outlook settings.
Note: Support for recurring (series) events while offline is not currently available.
This functionality is controlled by the existing mailbox policy setting:
OWAMailboxPolicy -OfflineEnabledWin.
If this policy is set to True, offline calendar functionality will be available. If set to False, it will be disabled. This update does not change the default value of the policy.
What you need to do to prepare:
Ensure that offline mode is enabled for users who need this functionality. At the user level, this can be verified in the new Outlook under:
Settings > General > Offline
- Enable offline email, calendar, and people
Admins can manage this setting using the Set-OwaMailboxPolicy cmdlet. Learn more here: Set-OwaMailboxPolicy
For end-user guidance, see: Work offline in Outlook
Compliance considerations:
- Does the change alter how existing customer data is processed, stored, or accessed? Yes – calendar data is now accessible and editable offline