Beta Notes

Allow changing the Spellcheck Language from status bar display

"New Message from Template" command

"Edit As New Message" will now use the account's default compose format, either HTML or plain text ignoring the format of the message. Plain text messages will be converted to HTML and vice versa. Then using the modifier, the format choice will be reverted.

The plain text to HTML conversion has been improved where such a conversion is necessary for "Edit As New Message" or when the shift modifier is used for "Edit Draft" or "New Message from Template".

The "Edit Draft" command now also honors the use of the shift key to convert HTML to plain text or vice versa when editing a draft

When attaching a message via drag and drop, the subject of the message is now used as attachment name instead of "Attached Message"

On first start, Thunderbird now shows the account setup dialog, no longer the account provisioner dialog

Thunderbird follows Firefox' Photon design with rectangular tabs and many other theme improvements

In Thunderbird 54 beta a better support for Charter users was introduced. As a side effect, messages moved to a different IMAP folder were immediately removed from the source folder, even when the delete model "Just mark it as deleted" was in effect. This has now been restored to its pre-version 54 state, so moved IMAP messages are only crossed out in the source folder when this delete model is used.

When many Thunderbird clients or other email clients accessed the same IMAP draft folder, messages were sometimes sent with the wrong identity. This has been corrected and the user will be notified if none of their identities matches the draft.

Passwords can now contain non-ASCII characters, like international characters, for example áäß, and symbols, for example €§

Certain add-ons would cause Thunderbird not to start