Just a few hours ago, it appeared that Microsoft's current build number for the Windows 8 Release to Manufacturing (RTM) candidate was 8523. Now the same web site that broke the news claims that the final version number of the RTM version will take a big jump.
Winunleaked.info (free registration required) claims that the sign-off build number for Windows 8 RTM will be 8888.16384.win8_rtm.120724-1555. Also, a Twitter post from the site's administrator "Canouna" says that a final sign off of the RTM candidate could happen later today at Microsoft or possibly early tomorrow.
Microsoft has already announced that it expects to complete the RTM build of Windows 8 sometime in the first week of August. We are only a week away from August 1st, so the timing seems to be pretty close
Once the final RTM version is achieved, it will be replicated on discs and sent to PC makers to install on new PCs, along with discs that will be packaged in retail stores; The official launch of Windows 8 is scheduled for October 26th.
The company has already announced that Windows XP, Vista and 7 owners can upgrade their PC to Windows 8 for just $39.99 from the time of its release to January 31, 2013. People who buy a new PC between now and January 31 will be able to get a Windows 8 update for just $14.99.