The third beta (build 14C81f) released on December 12, contained fixes for Wi-Fi, Mail, & VoiceOver issues. The public beta asks testers to focus on the same areas, suggesting that not much has changed in the two builds.
Users enrolled in the OS X Public Beta testing program can install the beta from the Updates tab of the Mac App Store.
If you’ve downloaded this new public beta build on your Mac, let us know if you found any new changes..