This article describes the major changes in Thunderbird version 13. For a complete list of bugs that have been resolved in the release, refer to the list of changes in Bugzilla.
Thunderbird now gives users the option of obtaining a new email account. In partnership with Gandi and Hover, we’ve made it possible to sign up for a new email address directly from within Thunderbird. After registering your personalized email address, Thunderbird will automatically set up the account and be ready to send and receive messages.
Our two partners are based Europe and North America respectively. Anyone can sign up with either company, but if you want a specific country domain (such as “.us” or “.fr”), select the provider in your geographic area. We are working with additional suppliers to cover more areas of the world and to provide more options in the future.
See the New Email Address article for instructions.
If you change the password for your Hover.com account using the web interface at hover.com, you may see an error message saying that Thunderbird cannot connect to the server. (This message will be something like "Server <firstname.lastname@example.org> has disconnected. The server may have gone down or there may be a network problem.") Thunderbird should instead prompt you to enter a new password. This issue will result in you not being able to send or receive messages in Thunderbird after changing your email password at hover.com.
Workaround: To send and receive emails with your Hover account again, you must delete the passwords in Thunderbird in order to force Thunderbird to prompt you for a new password:
This problem only affects Thunderbird 13. It has been fixed in Thunderbird 14.
Many email servers do not accept messages with large file attachments. The file size restriction varies depending on the mail server configuration. While you might be able to send a message with a large attachment, the receiving mail server might refuse to accept a message with a large attachment. This is all beyond the control of Thunderbird.
Thunderbird's new Filelink feature eliminates this problem by allowing you to upload attachments to an online storage service. The message attachment is replaced in the message with a link. The message recipient clicks the link to download the attachment. As additional benefits, sending and receiving large files is much faster and both you and the message recipient will save disk space.
See the Filelink for Large Attachments article for instructions.
The MD5 hash algorithm is no longer considered secure. If you are using certificates that are encrypted using the MD5 hash algorithm you should contact the certificate provider asking for an upgraded certificate that uses a more secure algorithm.
Windows XP SP 1 and earlier are no longer supported by Thunderbird.