Mozilla has released Thunderbird 18 Beta on November 29, 2012.
New features/fixes in Thunderbird 18 Beta include:
- Zoom functionality is now availabile [sic] in the compose window. Additionally, ctrl/cmd + and ctrl/cmd – now change the zoom setting rather than the font size.
- Various fixes and performance improvements
Users should be promoted to update shortly, or can check for updates via Help > About Thunderbird or downloading and installing Thunderbird 18 Beta from the Mozilla Thunderbird Channels page. Lightning users: When you update to Thunderbird 18 Beta, you should be automatically updated to Lightning 2.0b1 release. Thunderbird 18 final release will be in early January 2013.