DWYOR (Do it With Your Own Risk)
Want stable version? Wait for the Official/Final then. Because this version was launched on 17-07-2014 (Beta version).
Links from ASUS OTA update center.
Zenfone five WW Version A500CG/A501CG
Zenfone five TW Version A500CG/A501CG
Zenfone half dozen WW Version A600CG
Zenfone half dozen TW Version A600CG
How to Flash?
Flash WW Firmware v 1.15.40.35 in addition to then flash this zippo via ADB/Manual update
