KOrganizer vs Thunderbird: catalog facts
 KOrganizer |  Thunderbird |
|---|
|
Free Free and open source from the KDE community. |
Free Free forever, funded by donations. |
|
Linux |
Windows, macOS, Linux, Android |
- Works with Nextcloud, Kolab, Google Calendar and CalDAV servers
- Integrated to-dos alongside the agenda view
|
- Unified inbox across every account, or each account kept separate, your choice
- Mail, calendar, contacts and tasks in one application rather than four
|
- Best suited to the KDE Plasma desktop
- Depends on the Kontact/Akonadi stack
|
- The interface carries a lot of history and can feel dense next to a webmail tab
- Major ESR releases have historically been disruptive for add-ons and settings
|
|
Downloadable app |
Downloadable app |
|
Open source |
Open source |
|
License not stated |
License: MPL-2.0 |
|
No account needed |
No account needed |
|
Works offline |
Works offline |
Checked October 2, 2026 | Checked September 20, 2026 |
Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.
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