As we move ever closer to the October release, the latest build number for Microsoft's Windows 8 RTM has been leaked onto the Internet.

Microsoft’s newest operating system, Windows 8, is one of the most highly-anticipated operating systems in the past decade; for developers, it’s also one of the most nerve-wracking, with Microsoft CEO Steve Balmer announcing shortly after revealing the new operating system that the Metro interface would be built entirely with HTML5 and CSS3, leading to rumors that Windows 8 would ditch the tried-and-true languages and methods of desktop software development in favor of completely web-driven technologies. Microsoft quickly worked to dispel these rumors, reassuring developers that the rumors were misguided and that the Metro interface would be the only web-like piece of the operating system, programmatically speaking.

A few days ago, screenshots of a build of Windows 8 unreleased to the public somehow found their way onto the Internet, reportedly coming from the 8516 build of Microsoft’s newest OS. Now, the site which leaked those screenshots has reported that the current RTM, or Release to Manufacturing, candidate build number has gone above 8516. The RTM candidate is the version of the operating system which will be shipped to manufacturing centers to be burned onto discs and packaged for retail stores, and the build number is a method for Microsoft’s developers to keep track of the changes and updates that have been made to the code of the OS.

Winunleaked.info claims (registration required) that the current RTM build number is 8523.win8_rtm.120723-1815. If this is accurate it shows that Microsoft is continuing to tweak and improve the elements of Windows 8 as the final version looms closer and closer, with this most recent leaked build having been created on July 23rd at 6:15 PM local time (that’s what the numbers at the end of the build designation signify).

Many analysts expect that Microsoft will complete the RTM of Windows 8 sometime within the first week of August. When that happens, the build will be sent to PC makers in order to install on new PCs along with being sent to manufacturing centers in order to be prepared for retail release. The official launch of Windows 8 is scheduled for October 26th. Recently, Microsoft also announced that owners of Windows XP, Vista, and 7 will be able to upgrade their PC to Windows 8 for just $39.99 from that day to January 31, 2013. Anyone buying a new PC with Windows 7 will also be able to upgrade at a reduced price, with their price being just $14.99.