|The weekly release of new builds of the forthcoming OS X Mountain Lion 10.8.4 are continuing apace, with build 12E47 now available for testers -- again with no new changes or known issues, and again asking developers to focus testing efforts on the same areas as before: graphics, Safari and Wi-Fi performance. Earlier builds of 10.8.4 are known to be slightly improving battery life, addressing bugs with Wi-Fi stability and reconnection after waking from sleep, as well as fixing some remaining Nvidia card graphic glitches.
Previous builds of 10.8.4 were also noted to contain compatibility code for as-yet-unreleased Macs that would have 802.11ac Wi-Fi chips, which could hint of forthcoming models. Apple may be using the code in 10.8.4 as a testbed for compatibility in the future 10.9, which it will preview at the Worldwide Developer's Conference next month and may release in the weeks following the convention.
The 802.11ac protocol will be backwards-compatible with 802.11g and n standards, and acts as a kind of successor to 802.11n -- using the same 5GHz band but promising significantly faster network speeds and greater range. The 802.11ac standard has not yet been formally ratified but is complete, allowing products to be created using the protocol -- with any minor final revisions handled by firmware updates.
Currently, no existing Mac or iOS products support 802.11ac in hardware, but routine "spec bump" revisions -- such as possible refreshes of the MacBook line that may be announced at the WWDC -- would add the capability. No timeframe has been given for the release of a final version of 10.8.4, though its predecessor 10.8.3 received an unusual 13 betas prior to release.