|Apple is now seeding a fifth beta of OS X 10.8.5 to developers. The latest build, 12F23, is just a few version numbers advanced since the previous one, 12F20. That could mean that v10.8.5 will reach the public by the end of the month.
There are no known issues with 12F23. Apple is asking developers to continue testing components like graphics, Wi-Fi, wake-from-sleep functions, mobile device management, and PDF viewing and accessibility.