Neowin reports that a new update on a reliable third-party Windows 8 build number list shows that the current Release to Manufacturing (RTM) candidate build number has gone up to 8523

Microsoft is expected to complete the RTM build of Windows 8 sometime in the first week of August. Once that happens, the final build will be replicated on discs sent to PC makers to install on new PCs, along with discs that will be packages 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.

  Windows 8 RTM build number reportedly goes up to 8523