Thunderbird 60 will migrate security databases (key3.db, cert8.db to key4.db, cert9.db). Thunderbird 60.3.2 and earlier contained a fault that potentially deleted saved passwords and private certificate keys for users using a master password. Version 60.3.3 will prevent the loss of data; affected users who have already upgraded to version 60.3.2 or earlier can restore the deleted key3.db file from backup to complete the migration.
Address book search and auto-complete slowness introduced in Thunderbird 60.3.2
Plain text markup with * for bold, / for italics, _ for underline and | for code did not work when the enclosed text contained non-ASCII characters.
While composing a message, a link not removed when link location was removed in the link properties panel.
Decoding problems for messages with less common charsets (cp932, cp936). This will be fixed in version 60.4.0.
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