Short Version
Microsoft is expanding M365 Copilot capabilities in Outlook to include shared and delegated mailboxes. Due early May to early June 2026.
Details
This update allows M365 Copilot users to use Copilot features while working in shared or delegated mailboxes.
Main points:
- Access Copilot Chat in Outlook while working in a shared or delegated mailbox.
- Copilot features such as Summarise and Draft will work in shared and delegated mailboxes.
- Support includes full-access shared mailboxes and shared folder permissions.
- You will no longer need to include mailbox-specific phrases such as “in <mailbox>@domain.com” when prompting Copilot. Prompts can be written as if the mailbox is your own, and responses are grounded in the active shared mailbox.
- Copilot conversation history is saved to your primary account, ensuring that conversation history is not shared between users who access the same shared mailbox.
Availability
Due early May to early June 2026.
Source, related links, and references
MC1246031.
365 Roadmap ID 554936.
See what’s new in Copilot and Outlook.
Page originally published
8th March 2026, and kept up to date.
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