Thunderbird Desktop
Version 65.0beta | Released December 30, 2018
Check out the notes below for this version of Thunderbird. As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla.
These release notes apply to Thunderbird version 65 beta 4 released January 29th, 2019.
What’s New
new
FileLink for WeTransfer
new
WebExtensions FileLink API to facilitate FileLink add-ons. WeTransfer is already included and Dropbox is available as add-on.
new
Various theme improvements including a dark message list/thread pane
new
When multiple language packs are installed, the UI language can now be selected in the Advanced Options. Preference intl.multilingual.enabled needs to be set (and possily also extensions.langpacks.signatures.required needs to be set to false)
What’s Changed
changed
**ADD-ON SUPPORT: Restartless add-ons continue to work if their authors have made the necessary minor adjustments. Non-restartless legacy add-ons using XUL overlays are only supported if add-on authors have adapted them. ** Apart from Lightning/Calendar there are a few that have been adapted, like "ThunderHTMLedit", "Compact Header" and "Signature Switch". Instaling legacy add-ons now requires a restart. Legacy add-ons can now specify an options page again.
changed
** DICTIONARY SUPPORT: Only WebExtension dictionaries are supported now.** Please download new dictionaries from addons.mozilla.org since addons.thunderbird.net still provides "legacy" dictionaries compatible with Thunderbird 60 ESR. This may change as soon as Thunderbird 60 ESR can also handle WebExtension dictionaries (planned for version 60.5).
changed
Reply to self will now search all identities (default of preference mailnews.reply_to_self_check_all_ident changed to true)
changed
Composition text and background colors no longer sent by default. New option in "Tools > Options, Composition".
What’s Fixed
fixed
Address book search and auto-complete slowness introduced in Thunderbird 64 beta
fixed
Plain text markup with * for bold, / for italics, _ for underline and | for code did not work when the enclosed text contained non-ASCII characters
fixed
While composing a message, a link not removed when link location was removed in the link properties panel
fixed
Decoding problems for messages with less common charsets (cp932, cp936)
fixed
Spurious 
 (encoded newline) inserted into drafts and sent email
fixed
Double-clicking on a word in the Write window sometimes launched the Advanced Property Editor or Link Properties dialog
fixed
Editing a plaint text draft displayed the entire message as quote (in blue)
fixed
New messages in the drafts folder (and other special or virtual folders) will no longer be included in the new messages notification
fixed
Edit > Undo didn't undo moving or deleting of messages
fixed
Improvements of SMTP 5.7.1 message
Beta 2
What’s New
new
Thunderbird now allows the addition of OpenSearch search engines from a local XML file using a minimal user inferface: [+] button to select a file an add, [-] to remove.
new
During account creation, Thunderbird will now detect servers using the Microsoft Exchange protocol. It will offer the installation of a 3rd party add-on (Owl) which supports that protocol.
What’s Fixed
fixed
Account creation sometimes shows an error: "Programming bug. Assertion failed, see log"
fixed
Chat: Participants not sorted (not working since Thunderbird 63 beta)
Beta 3
What’s New
new
More search engines: Google and DuckDuckGo available by default
What’s Fixed
fixed
Crash when using "Send to > Mail recipient" on Windows under some circumstances (MAPI interface)
Beta 4
What’s Fixed
fixed
Full Unicode support for MAPI interfaces: New support for MAPISendMailW, UTF-8 support for MAPISendMail
fixed
Chat: Participants not sorted (follow-up)
fixed
Calendar print preview not working
fixed
CalDav access to some servers not working
Known Issues
unresolved
Due to changes in the Mozilla platform profiles stored on Windows network shares addressed via drive letters are now addressed via UNC
unresolved
Spellcheck marks disappeared erroneously for words with an apostrophe (working in Thunderbird ESR)
unresolved
Calendar: A localized version of Provider for Google Calendar not available at addons.thunderbird.net or the Mozilla FTP server. A US-English version can be downloaded here.
unresolved
Chat: Twitter not working due to API changes at Twitter.com