Ben Poon posted on the Mail Call that the next version of the Windows Live Mail “M9” beta is being deployed. What's new with this M9 build? First and foremost, it’s faster, even though it has more features!
Next, is “Classic mode” previously known as “Light” —implmented on users feedback, as they do like the Classic experience as a nice transition before switching to the “Full” experience of Windows Live Mail. So we’re switching things up a little! When an account is first migrated over, it will automatically start out in the Classic experience, allowing the user to decide if and when to move up to the Full experience. Even better, moving forward, everyone can switch between the Classic and the Full experiences in the Options section anytime. For those of you who currently have existing Windows Live Mail accounts, your existing settings will be preserved, so if you’re on the Full experience now, you’ll stay there (with the option to change to Classic if you ever choose to).
The migration from M8 to M9 is being phased in, so if you're using Windows Live Mail and don't see any difference (the new build is 11.09.0000.0119), then you should be seeing it within a week or so.