Thunderbird 140 Released: Dark Mode, Easy Setting Sync, and Exchange Support
2025-07-09
Thunderbird email client version 140 is out, boasting several new features. A standout is "dark message mode," adapting message content to dark themes. It also features easy transfer of desktop settings to the mobile Thunderbird client, experimental Microsoft Exchange support, and global controls for message threading and sort order. This is an extended-support release (ESR) with 12 months of support, though Thunderbird encourages users to switch to the monthly Release channel. A staggered rollout to existing users helps catch bugs before widespread deployment, but manual upgrades are available via Help > About. Check the release notes for a complete changelog.
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