Outlook: Support for storing S/MIME certificates in contacts in new Outlook

Updated May 27, 2026: We have updated the timeline. Thank you for your patience.  Introduction The new Outlook for Windows now allows users to store S/MIME encryption certificates directly within Contacts. This capability enables users to save recipients’ public certificates and use them to send S/MIME encrypted emails, improving secure communication and continuity when transitioning from classic Outlook for Windows (Win32). Certificates previously stored in Contacts in classic Outlook will automatically be available in new Outlook. This message is associated with Microsoft 365 Roadmap ID 518288. When this will happen: General Availability (Worldwide): We will begin rolling out in late May 2026 (previously mid-May) and expect to complete by mid-June 2026 (previously late May). General Availability (GCC): We will begin rolling out in mid-June 2026 (previously early June) and expect to complete by late June 2026. How this affects your organization: Who is affected: Users of new Outlook for Windows Organizations that use S/MIME encryption What will happen: Users can store recipients’ S/MIME public certificates directly in Contacts. Screenshot: To add a S/MIME certificate, go to Your contacts > Certificates > Add certificate: Stored certificates can be used to encrypt outgoing email to those recipients. Certificates saved in Contacts in classic Outlook (Win32) will automatically carry over. Feature is available by default; no admin configuration required. No impact to users who are not using new Outlook for Windows. What you can do to prepare: No admin action is required to enable this feature. If your organization uses S/MIME:Instruct users to add or import S/MIME public certificates into Contacts. Communicate how to select S/MIME encryption when composing emails. Learn more: Send S/MIME or Microsoft Purview encrypted emails in Outlook | Microsoft Support. Update internal documentation for users transitioning from classic Outlook. Inform helpdesk teams of this improved certificate handling experience. Compliance considerations: Area Explanation Does the change store new customer data? Classic Outlook already has this capability, and we are bringing it to new Outlook as well. S/MIME public certificates can now be stored in Outlook Contacts; these persist as part of contact data. Does the change alter how existing customer data is processed, stored, or accessed? Existing certificates stored in classic Outlook Contacts are now accessible in new Outlook, improving continuity.