Thunderbird 78.0

What's new in this version:

New:
- New Account Hub for centralized account setup
- Redesigned recipient address fields (To, Cc, Bcc) as single-line input fields (pills) for multiple addresses instead of one line per address. More improvements to come.
- Color customization of Folder Pane icons
- Allow selecting messages via selection boxes instead of classic selection. "Select Messages" column needs to be selected via the thread pane's column picker.
- "Delete" action column in thread pane (message list). "Select Messages" column needs to be selected via the thread pane's column picker.
- Themes can be previewed in the Add-On Manager
- Minimize to tray support added for Windows
- New config option to anonymize message date header
- Global Search menu item in app menu
- Additional Enterprise policies
- Calendar: Added ICS import support to -file command line option
- Calendar: Add event preview to ICS import dialog
- Chat: OTR messaging support
- Chat: IRC echo-message capability

Changes:
- Add-on support: As of version 78.0, Thunderbird only supports MailExtensions and MailExtension Experiments. Restartless add-ons and non-restartless legacy add-ons using XUL overlays are no longer supported.
- Linux minimum runtime requirements have changed: GTK 3.14, GLIBC 2.17, libstdc++ 4.8.1 Details
- Thunderbird Options/Preferences tab redesigned and with new user interface
- Account creation dialog redesigned and with new user interface
- Account Manager moved to a tab
- Add-ons manager with new user interface and notifications
- Improved "Recent" folder list for "Move to" and "Copy to" in message context menu
- Improved UI of global search results tab
- Improvements to the location bar of a tab displaying web pages
- Use scalable icons throughout Thunderbird to improve support for HiDPI monitors and dark mode
- Thunderbird will now ask for OS account password before displaying saved passwords
- Address books are now stored as SQLite databases to prepare for future addressbook improvements. Existing address books in MAB format (using a Mork database) will be converted.
- New parser and formatter for vCard. vCard versions 3.0 and 4.0 are now supported.
- Various theme and dark mode improvements
- Various look and feel improvements
- Improved dialog for folder compaction (purging of deleted messages)
- Graphics hardware acceleration is now enabled by default
- TLS 1.0 and 1.1 disabled
- Calendar: The Lightning calendar add-on is now integrated into Thunderbird
- Calendar: Lightning version removed from Thunderbird user agent string
- Calendar: Web Calendar Access Protocol (WCAP) support removed
- Calendar: Storage access is now asynchronous to improve performance
- Calendar: Location URLs are now clickable
- Addon Developers: Updates to and expansion of MailExtensions APIs. Details

Fixes:
- Password display font had characters that were difficult to read
- When copying messages from an IMAP folder to a local folder, offline store wasn't used
- While Thunderbird was in safe mode, the help menu did not offer an item to restart with add-ons enabled
- Mailbox quotas not displayed correctly
- Images not rotated when composing a message
- Email addresses sometimes displayed incorrectly in message composer
- Many accessibility fixes and improvements: message composer, account setup, attachment pane
- Mailbox format conversion fixes
- Address book improvements: exporting, editing contacts, contact photos
- Chat: Renaming contacts in context menu did not work
- Calendar: Task and event dialogs were sometimes too small for their content
- Calendar: URLs in the event reminder dialog were not clickable
- Various security fixes