Thunderbird is a free, open-source, cross-platform application for managing email and news feeds. It is a local (rather than a web-based) email application that is powerful yet easy-to-use. Thunderbird is developed, tested, translated and supported by the folks at Mozilla Corporation and by a group of dedicated volunteers. Thunderbird gives you control and ownership over your email. There are lots of add-ons available for Thunderbird that enable you to extend and customize your email experience.
Thunderbird gives you IMAP/POP support, a built-in RSS reader, support for HTML mail, powerful quick search, saved search folders, advanced message filtering, message grouping, labels, return receipts, smart address book LDAP address completion, import tools, and the ability to manage multiple e-mail and newsgroup accounts.
What's new in Thunderbird 78.7.1:
CardDAV address books now support OAuth2 and Google Contacts.
Thunderbird will no longer allow installation of addons that use legacy APIs
Send message button sometimes remained enabled when it should be disabled
Pressing command+enter to send a message on macOS did not work
OpenPGP: Failed to save attachments that contained binary data after decryption
Global search UI fixes
Various theme and color fixes to improve ease of use
Download: Thunderbird 78.7.1 for Windows (EN/US) | 64-bit | ~50.0 MB (Open Source)
Download: Thunderbird 78.7.1 for Linux (EN/US) | 65.2 MB
Download: Thunderbird 78.7.1 for Mac OS (EN/US) | 66.4 MB
Download: Thunderbird 78.7.1 in other languages
View: Thunderbird Website | Release Notes | Screenshot