People involved in the beta testing process told AppleInsider that the latest version bears build number 13D28. The company did not release a coinciding beta update to the Xcode suite or the operating system's server variant.
Apple does not report any known issues with the newest build, but focus areas remain the same as they have in previous editions. This represents the fourth OS X 10.9.3 beta since the process began.
Previous betas have added support for pixel-doubled "Retina" mode with 4K monitors and contact and calendar synchronization through iTunes.
Registered Mac developers can download the OS X Mavericks 10.9.3 build 13D28 from the Mac Dev Center.