Ask anybody who's ever written a certification or an OS book what "day and date" means, and you will quickly get an intense earful about the difficulties that attach to preparing materials for print or other forms of content delivery to coincide precisely with a specific, planned (and often publicly announced) release date. That's one thing that makes it so very, very interesting that Microsoft is declining to share its so-called "RTM" (release to manufacturing) release with developers and other industry insiders who are still expected to support the upcoming release anyway.
The problem, of course, is that an inability to work with the OS prior to its actual public release means that efforts to document it, explain it, or derive certification exam questions (and all the information edifices that surround such things) have to be based on guesswork, at least in part. MS is currently recommending that developers (and presumably also, trainers and certification writers) focus their efforts on the currently available Windows 8.1 Preview, released on June 26, 2013. But a certain amount of optimism is required to ask these people to hang months of intense professional effort on a code snapshot that's bound to change, perhaps even in substantial ways, between that time and the mid-October date for the upcoming General Availability (GA) release.
A commenter to an article from yesterday's The Verge ("Windows 8.1 leak on the web ahead of its October release") summed this situation up very nicely when he said
“RTM” doesn’t mean “finished” anymore. :-\ [aaron44126]It seems like Microsoft is making things hard for some of its key constituents -- namely certification and training experts charged with teaching (or testing) the world about the new platform, and developers responsible for building the apps that give Windows 8 its cache and such charm as it may be supposed to possess. I'm having a little trouble understanding why they would do this, but must concede that the prevailing opinion -- namely, that the so-called RTM version of 8.1 simply isn't yet ready for prime time or production use -- has to be true.