SeaMonkey  2.20 Beta 1
* The Content Security Policy (CSP) 1.0 parser has been enabled.
* The Mixed Content Blocker has been enabled, blocking insecure active content loads on HTTPS pages.
* New mail alert information can be customized now (Preferences/Mail & Newsgroups/Notifications).
* A confirmation prompt has been introduced to protect against accidental permanent data loss when force-deleting messages using Shift+Del.
* MailNews Save As Template supports multiple selections now.
* The size on disk is now shown for newsgroup folders.
* The Publish Webpage prompt in Composer has been fixed.
* Reporting a phishing site no longer sends potentially sensitive information from query parameters.
* POP3 local inbox folders no longer grow past the 4 GB limit when getting mail.
* MailNews search, filter and mail views no longer include messages on the date with "date" "is after"/"is before".
* Session restore now ensures restored windows are actually on-screen.
* The search bar no longer saves the search history in private windows.
* The SSL Preference pane has been updated to accommodate changed preference names and semantics.
* Crtl+clicking a link opens it now even if the click event handler calls event.stopPropagation().
* The Get Mail popup menu is now restored to full width after customizing the toolbar.
* MailNews folder size checks check the available disk space now.
* Attaching a message without trailing line break no longer corrupts the attachment.
* The browser feed preview has been adapted for Private Browsing.
* The MailNews subscribe dialog has been improved (the server of the selected folder is now selected and subscription checkboxes are now accessible).
* Balloon notifications on new mail are no longer shown if the tray icon is disabled.
* Compacting large mail folders should be more stable now.