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ThunderbirdGNOME Calendar
Free

Free forever, funded by donations.

 Free

Free GNOME application supported by donations.

Windows, macOS, Linux, Android Linux
  • Unified inbox across every account, or each account kept separate, your choice
  • Mail, calendar, contacts and tasks in one application rather than four
  • Syncs with Nextcloud, Google Calendar and CalDAV servers
  • Local calendars work fully offline
  • 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
  • Designed for the GNOME desktop on Linux
  • Kept deliberately simple, with fewer features than full groupware clients
Downloadable app Downloadable app
Open source Open source
License: MPL-2.0 License not stated
No account needed No account needed
Works offline Works offline

Checked September 20, 2026

Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.