Recently Updated Extensions
CardBook Requires Restart Featured
CIX Forums Requires Restart
Open CIX Forums in Thunderbird. Free CIX accounts from https://forums.cix.co.uk/signUp.aspx?p=cixbasic
HTTPS Everywhere Requires Restart
Encrypt the web! HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.
Finally, an efficient blocker. Easy on CPU and memory.
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
Stylish-Custom Requires Restart
custom additions to Stylish extension
Lightning Calendar Tabs Requires Restart
Displays tabs which allows quick navigation between time periods in Lightning calendar. All views of calendar are supported. Color of tab texts can be adjusted.
'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions.
Beta builds on versions page!
Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.
Auto Resize Image Requires Restart
Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).
Grammalecte [fr] (for Thunderbird) Requires Restart
French grammar checker. Included: conjugation tool, text formatter and spelling dictionaries.
Nextcloud for Filelink NG Requires Restart
"Nextcloud for Filelink" is an Open Source Thunderbird extension which makes it easy to send large attachments with Thunderbird by uploading them first to a Nextcloud server and by then inserting the link into the body of your email.
Add menu commands for replying to multiple messages at the same time.
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
attachment column in search result list Requires Restart
Show the column for attachments in search results list. General search (edit-> search -> search emails) does not show by default if a message has attachments.
This addon adds this column, just as in a normal folder view.
Send YouTube video links to an external player, downloader, etc,
CardDAV Browser Requires Restart
A utility to browse vCards stored on a CardDAV server.
Blend In Requires Restart
Blends in OS-related values in User-Agent HTTP request header & a number of JS properties, so that Firefox (Thunderbird) appears to sites visited as running on the OS being used the most in the world. Thunderbird can also be blended in as Firefox.
WarnAttachment Requires Restart
WarnAttachment shows an additional dialog to confirm potentially dangerous attachments. Some attachments like executables etc. are completely blocked. This reduces the risk of malware especially for inexperienced users.