After releasing the initial beta in December, Apple just released the fourth beta of Mac OS X 10.9.2 Mavericks (build 13C48).
As a reminder, beta 1 mainly added functionality FaceTime audio introduced on devices iOS 7 (read: Mac OS X 10.9.2 beta 1: arrival of FaceTime Audio). The following updates, for their part, included the possibility of blocking certain iMessage or FaceTime users.
For this fourth beta, Apple asks developers to focus on Mail, Messages, graphics drivers, VoiceOver, VPN as well as SMB2 (Service Message Block).
You can get the update from the Mac Developer Center at this address or via the Software Update if you?re already on OS X 10.9.2. If you see any news, please let us know in the comments!