* Improved Vertical view
* Improved compose window
* Inline quick reply
* Enhanced font size controls
* Improved message view
* Improved unread indicators in folder and focus pane
* Added support for playing a sound on send. Go to Preferences | Compose | Advanced to enable sound on send.
* Added support for Redirect via the Message menu and toolbar button (you must add the toolbar button through the Customize Toolbar function).
* Support for color and monochrome icons on Mac OS X (customize the toolbar to select a color or monochrome set).
* Added a toolbar icon to open and close the Inspector.
* Use Spotlight search to find messages by Topic keywords
* Added a remove text formatting button to the HTML format bar in compose.
* Lots of pixel pushing to make Postbox look awesome!
* IMAP support for Yahoo! Mail
* Improved migration and account setup wizard on Mac OS X.
* Improve UI for add-ons manager, account setup wizards for RSS and Newsgroups on Mac OS X.
* Replaced the Status Bar with an inline notification pop-up panel.
* Improved progress when loading messages
* New inline junk mail notification bar.
* Moved Search Options Panel button to within the Search Bar on Mac OS X.
* Attachment size should be visible in compose window
* Simplified "Insert Link" dialog in message compose
* Fixed an issue with twitter authentication
* Support CC and BCC and multiple attachments in AppleScript
* Bolding of unread messages in vertical view now configurable via a hidden preference.
* Performance improvements
* Stability improvements