Mozilla Automation TeamEleanor Dicharry5 min readintermediate
Thunderbird Desktop New Protocol Support: Microsoft Graph API
Summary
Thunderbird 154 adds native Microsoft Graph API support for Microsoft 365 email, replacing EWS which will be shut down in 2026‑27. Users must delete their EWS account and set up a new Graph account; calendar and address book support are still pending.
- Thunderbird now supports Microsoft Graph API for Microsoft 365 email; required after EWS shutdown in Oct 2026.
- Migration involves deleting the existing EWS account in Thunderbird and creating a new account using the Graph option; no data loss.
- Graph support is email‑only; calendar and address book are not yet implemented and are unavailable in ESR (v153).
- The new extensible email client architecture reduced implementation time from 11 months (EWS) to 4 months (Graph), paving the way for future protocols like JMAP.
Thunderbird users on Microsoft 365 need to switch to Graph to maintain email access, and developers can study the extensible design for adding new protocols.
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