Beta Notes

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, and Lightning/Calendar is the only one we know that has been adapted.

Changed UI when installing add-ons. Restart required for legacy extensions.

Calendar: UI improvements for event dialog

Print preview not working in Thunderbird version 63 beta

Various Theme fixes where incorrect colors, backgrounds, etc. were displayed. Folders with new messages not shown in bold on Mac.

Add-on Options menu not working on Mac

Shift+PageUp/PageDown in Write window

Saving content of Write windows didn't overwrite existing file

Issues related to "Edit Template" command

Gloda attachment filtering

S/MIME encryption/signing not working in Thunderbird version 63 beta

Body search/filtering didn't reliably ignore content of tags

Mails won't get removed from Trash folder using Maildir. Note: Other deletion issues related to Maildir still persist.

If the "Date" header of a message was invalid, Jan 1970 or Dec 1969 was displayed. Now using date from "Received" header instead.

Mailing list address auto-complete enter/return handling

When sending of a message failed due a security issue, only "unknown error" was displayed. Now more details are given.

"Select All" in mail view not working in Thunderbird version 63 beta

According to RFC 4616 and RFC 5721, passwords containing non-ASCII characters are encoded using UTF-8 which can lead to problems with non-compliant providers, for example office365.com. The SMTP LOGIN and POP3 USER/PASS authentication methods are now using a Latin-1 encoding again to work around this issue.

"Download rest of message" not working if global inbox was used

Shutdown crash/hang after entering an empty IMAP password

Cookie removal (not working since Thunderbird version 52)

Encoding problems for users (especially in Poland) when a file was sent via a folder using "Sent to > Mail recipient" due to a problem in the Thunderbird MAPI interface

Under some circumstances Thunderbird on Mac would send attachments using the so-called AppleDouble format which could 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.

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

New email not inserted in correct sort order in threaded unified view or search folder

Spurious 
 (encoded newline) inserted into drafts and sent email (working in Thunderbird ESR, will be fixed in version 65 beta)

Double-clicking on a word in the Write window sometimes launches the Advanced Property Editor or Link Properties dialog (working in Thunderbird ESR, will be fixed in version 65 beta)

Spellcheck marks disappeared erroneously for words with an apostrophe (working in Thunderbird ESR)

Editing a plaint text draft may display the entire message as quote (in blue) (working in Thunderbird ESR, will be fixed in version 65 beta)

Chat: Twitter not working due to API changes at Twitter.com

Chat: Participants not sorted