It's not clear why Microsoft made its initial decision, but Hilwa speculates it may have stemmed from its ongoing transformation into a devices and services company, a plan outlined in a broad reorganization launched in July by soon-to-be-retired CEO Steve Ballmer.
"I think they came to their senses to realize that their ecosystem of developers is different from Apple’s and prefers more open practices," Hilwa said.
Developers and IT pros get to download both the Pro and standard editions of Windows 8.1 RTM, as well as Windows Server 2012 R2 RTM and Visual Studio 2013 Release Candidate.
However, they will not get access to the RTM version of Windows RT 8.1, the version of the OS for devices that run ARM chips, according to a Microsoft spokesman. Hardware vendors did get access to Windows RT 8.1 RTM two weeks ago.
Guggenheimer said it will still be necessary for IT pros and developers to refine and tweak their Windows 8.1 applications and IT environments once the final, GA (general availability) version of the OS ships in mid-October.
However, the RTM version offers code that is much closer to the final build than the Preview version developers and IT pros received in late June at Microsoft's Build conference.
Microsoft had argued in its defense two weeks ago that the Preview versions of Windows 8.1 and Visual Studio were sufficiently baked for the purposes of IT pros and developers.
This was the latest flap involving Windows 8, a historically important upgrade to the company's flagship OS for desktops, laptops and tablets.
Windows 8 started shipping October of last year with a radically altered user interface called Modern, and also with a more traditional Windows 7-like desktop for legacy applications.
Based on tile icons and optimized for touchscreen devices, the Modern interface was designed to make Windows a better OS for tablets, where the Microsoft OS has taken a beating at the hands of Android and Apple's iOS.
Unfortunately, the Modern interface wasn't well received, particularly among enterprise and consumer buyers of Windows 8 laptops and desktops, who complained that it was hard to master and inconvenient to use with a mouse and keyboard.
With Windows 8.1, Microsoft is hoping to put out the main fires keeping customers away from the OS. For instance, it's adding something very close to the Windows 7 Start button, which the company took away in Windows 8, clearly unaware of how attached users are to it.
Windows 8.1 also attempts to smooth out the process of toggling between the Modern and traditional interfaces, which many users have described as awkward. To this end, it will be possible for Windows 8.1 users to boot directly to the traditional desktop interface.
Windows 8.1 also lets users view all the applications installed on their device and sort them by name, date installed, most used or category. The OS update also sports an improved search engine powered by Bing that will return results from a variety of sources, including the Web, applications, local files and the SkyDrive cloud storage service.
Windows 8.1 also comes with Internet Explorer 11, a new version of Microsoft's browser that the company has said will load pages faster and offer better performance in touchscreen mode.
Other Windows 8.1 enhancements include the ability to make a Skype call and take photos with the Windows 8.1 device while the screen is in Lock mode without having to log in. It will be possible as well for users to select multiple applications at once and perform bulk actions on them, like resizing, uninstalling and rearranging them.
Juan Carlos Perez covers enterprise communication/collaboration suites, operating systems, browsers and general technology breaking news for The IDG News Service. Follow Juan on Twitter at @JuanCPerezIDG.