Thunderbird has always been underperforming when measured against its own roadmaps. Now it looks like the roadmaps have been replaced by a list of what the project is working on anyway.
Let's compare the past and current roadmaps. We're focusing on the major items which have accompanied us over the last five years, of which at time of writing (April 2026) none are complete and only one, Exchange support, has a realistic chance of being completed.
| Feature | Roadmap 2021 / 91 | Roadmap 2022 / 102 | Roadmap 2023 /115 | Roadmap 2024 / 128 | Roadmap 2025 / 140 | Roadmap 2026 / 153 |
|---|---|---|---|---|---|---|
| Fluent Migration | planned / incomplete |
no mention / incomplete |
no mention / incomplete | planned / incomplete |
planned / incomplete | no mention / incomplete*) |
| Protocols in JS | SMTP planned / completed |
NNTP+POP complete, IMAP JS incomplete | no mention | no mention | (IMAP JS removed) | |
| JMAP | planned | no mention | no mention | no mention | no mention | no mention |
| Movemail | removal planned / removed |
(removed) | (removed) | (removed) | re-implementation planned / (removed) |
no mention |
| Filters in JS | planned | planned | no mention | no mention | rewrite planned | no mention |
| Global Database + Kill Mork |
planned / incomplete |
planned / incomplete |
planned / incomplete |
planned / incomplete |
planned / incomplete |
planned / incomplete |
| Exchange, EWS, Graph | planned / incomplete |
planned / incomplete |
planned / incomplete*) |
|||
| Account Sync | planned / incomplete |
planned / incomplete |
no mention | |||
| System tray | planned / incomplete |
no mention |
Items marked with an asterisk for 2026 (Fluent, Exhange) may be complete for the summer release of Thunderbird 153, the global database will not be shipping in this release.
Important items, like replacing the buggy 26-year-old MIME library of finally providing a decent and contemporary mail editor, are not even on the roadmap.
It's no surprise that things are not progressing with the Thunderbird desktop development, since despite close to 60 staff (of whom 15 are managers, CEO, COO or directors), the project has "diversified" into Thunderbird for Android (rebadged K-9 app), Thunderbird for iOS and so-called "Services" where the project actually supplies mail accounts. A developer recently wrote that the desktop team was small; going by the mentioned page and not counting director/manager and release engineer, there are only 12 people.