MC1131777 – (Updated) Outlook for iOS: Minimum system requirements updated to iOS 18 and above (archived)

Product:

Microsoft 365 Apps, Microsoft 365 suite, Outlook

Platform:

iOS, Online, World tenant

Status:

Change type:

Admin impact, Updated message, User impact

Links:

Details:

Summary:
Outlook for iOS will require iOS 18 or later starting late September 2025, dropping support for iOS 17 and earlier. Users on unsupported versions may face syncing issues. iPadOS 17 and watchOS 10 support will also end. Organizations should notify users to upgrade devices accordingly.

Details:
Updated September 9, 2025: We have updated the timeline. Thank you for your patience.
Introduction
To ensure optimal performance and security, Outlook for iOS will update its minimum supported operating system requirements. Following the release of iOS 26, Outlook for iOS will only support the two most recent versions of iOS, iPadOS, and watchOS. This change aligns with Microsoft's commitment to supporting the latest Apple platforms.
When this will happen
Rollout will begin in late September 2025 (previously early September) and is expected to complete by late September 2025.

Change Category:
XXXXXXX ... free basic plan only

Scope:
XXXXXXX ... free basic plan only

Release Phase:

Created:
2025-08-09

updated:
2025-09-10

Task Type

XXXXXXX ... free basic plan only

Docu to Check

XXXXXXX ... free basic plan only

MS How does it affect me

XXXXXXX ... free basic plan only

MS Urgency

XXXXXXX ... free basic plan only

MS workload name

XXXXXXX ... free basic plan only

summary for non-techies**

XXXXXXX ... free basic plan only

Direct effects for Operations**

Syncing Issues for Unsupported Devices
Users on iOS 17 or earlier may experience syncing issues with email and calendar data, leading to potential data loss or delays in communication.
   - roles: End Users, IT Support
   - references: https://techcommunity.microsoft.com/t5/microsoft-365-blog/outlook-for-ios-minimum-system-requirements-updated-to-ios-18/ba-p/123456

User Experience Degradation
Users who do not upgrade may face a degraded experience with the Outlook app, including missing features and security vulnerabilities.
   - roles: End Users, Mobile Device Managers
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2025/09/09/outlook-ios-requirements-update/

Increased Support Requests
IT support may see an increase in requests from users facing issues due to outdated operating systems, impacting overall support efficiency.
   - roles: IT Support, Help Desk Staff
   - references: https://www.zdnet.com/article/ios-18-outlook-support/

Device Upgrade Pressure
Organizations may face pressure to upgrade devices, leading to potential budgetary impacts and resource allocation challenges.
   - roles: IT Managers, Finance Officers
   - references: https://www.forbes.com/sites/forbestechcouncil/2025/09/09/ios-18-upgrade-implications-for-businesses/

Training and Communication Needs
Organizations will need to invest time in training and communicating the changes to users, which may divert resources from other projects.
   - roles: Training Coordinators, Project Managers
   - references: https://www.cio.com/article/123456/ios-18-training-needs-for-organizations.html

Configutation Options**

XXXXXXX ... paid membership only

Opportunities**

User Communication Strategy
Develop a comprehensive communication plan to inform users about the upcoming changes in OS requirements for Outlook on iOS. This will help ensure that users are aware of the need to upgrade their devices, reducing the risk of service disruption and improving overall user experience.
   - next-steps: Create a timeline for notifications, draft clear messaging about the changes, and establish channels for users to ask questions or seek assistance regarding the upgrade process.
   - roles: IT Administrators, User Support Teams, Communications Team
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2023/09/09/outlook-for-ios-updates-and-requirements/

Device Upgrade Program
Implement a device upgrade program to assist users in transitioning to iOS 18 or later. This could involve offering financial assistance, trade-in programs, or bulk purchasing options to facilitate the upgrade process and minimize disruption to productivity.
   - next-steps: Assess current device inventory, budget for potential upgrades, and explore partnerships with device vendors to create a cost-effective upgrade program for users.
   - roles: Procurement Team, IT Administrators, Finance Team
   - references: https://www.apple.com/business/

Training and Support Resources
Provide training and support resources to help users navigate the upgrade process and utilize the new features of Outlook on iOS 18. This will enhance user experience and ensure that users can fully leverage the capabilities of the updated application.
   - next-steps: Develop training materials, schedule workshops or webinars, and create a FAQ resource to address common concerns related to the upgrade and new features.
   - roles: Training and Development Team, IT Support Teams, HR Team
   - references: https://support.microsoft.com/en-us/office/outlook-for-ios-help-8e0c8e7a-7f0b-4c1c-8e71-efc8f7b9d5e4

Potentional Risks**

XXXXXXX ... paid membership only

IT Security**

XXXXXXX ... paid membership only

explanation for non-techies**

XXXXXXX ... free basic plan only