Apple has seeded the fourth beta of Mac OS X Mavericks version 10.9.2 after releasing the initial beta back in December
. The first beta of 10.9.2 included FaceTime Audio with build number 13C32. Today's 10.9.2 beta 4 is build 13C48, bringing the update closer to a retail release. Previous betas also brought the ability to block certain iMessage or FaceTime users.
The focus areas including Mail, Messages, Graphics Drivers, VoiceOver, VPN and SMB2.
You can grab the update in the Mac Developer Center or via Software Update if you are currently on 10.9.2. Let us know if you spot anything!