Apple is rapidly running out of time to make their promise that iOS 4.2 would launch in November. The company released a new gold master build for iOS 4.2, 4.2.1, late Thursday.

As opposed to the earlier re-released GM build, which was for iPad only, this build is across all devices supported by iOS 4.x. The build is number 8C148, and reportedly fixes major Exchange and audio issues that have been documented on Apple’s developer forums.

Normally we would expect this to delay the release of iOS 4.2 by another week. The most recent rumored date was Nov. 24th. However, according to the report, Apple QA has been told to complete testing on the new build by this weekend, "no matter what." That points to Apple attempting to keep the release to that schedule.