💡 Our Technical Review in summary
Microsoft is enhancing the “new” Outlook for Windows by introducing offline capabilities for the calendar. This update allows users to create, edit, and delete single calendar events without an active internet connection. Once the device reconnects, these changes will automatically synchronize with the server. This feature addresses a significant functionality gap between the classic Outlook desktop client and the new web-based Outlook interface.
#### Impact
- Enhanced Productivity: Users can manage their schedules during travel or in areas with poor connectivity.
- Feature Limitations: This update currently only supports single calendar events. Offline support for recurring events (series) is not included in this rollout.
- Synchronization Constraints: To edit or delete an existing event while offline, that event must have been previously synchronized within the local offline timeframe configured in the user’s settings.
- Compliance & Security: Because calendar data is now stored and accessible locally for offline use, organizations with strict data residency or local storage policies should review their compliance posture.
- Administrative Control: This feature is governed by the
OfflineEnabledWinparameter within theOWAMailboxPolicy.
#### Action Required
- Review Policy Settings: Use the
Get-OwaMailboxPolicycmdlet to check the status ofOfflineEnabledWin. Ensure it is set to True for users who require this functionality. - Configure via PowerShell: If changes are needed, use the
Set-OwaMailboxPolicycmdlet to enable or disable the offline feature across specific user groups. - User Configuration: Instruct users to verify their local settings in the new Outlook for Windows under Settings > General > Offline, ensuring “Enable offline email, calendar, and people” is toggled on.
- Internal Documentation: Update your internal help desk resources to clarify that recurring series updates are not yet supported in offline mode to manage user expectations.
- Deployment Timeline: Monitor the rollout starting in late October 2025, with full global availability expected by early February 2026.
Microsoft Official Update
Service: N/A
Category: planForChange
Severity: normal
Updated January 23, 2026: 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 early February 2026 (previously mid-December 2025).
[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
