Thunderbird 60.3.2

Thunderbird

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 fixed in Thunderbird 60.3.2:

Under some circumstances Thunderbird on Mac will send attachments using the so-called AppleDouble format which can lead to problems with mail servers and recipients
Encoding problems when exporting address books or messages using the system charset. Messages are now always exported using the UTF-8 encoding.
If the "Date" header of a message was invalid, Jan 1970 or Dec 1969 was displayed. Now using date from "Received" header instead.
Body search/filtering didn't reliably ignore content of tags
Inappropriate warning "Thunderbird prevented the site (addons.thunderbird.net) from asking you to install software on your computer" when installing add-ons
Incorrect display of correspondents column since own email address was not always detected
Spurious 
 (encoded newline) inserted into drafts and sent email
New email not inserted in correct sort order in threaded unified view or search folder

Known Issues:

CalDav access to some servers not working. Workaround: Set preference network.cookie.same-site.enabled to false.
Chat: Twitter not working due to API changes at Twitter.com