The forked version, dubbed Open Live Writer, can be downloaded from the group's website. The download is approximately 4.6MB in size.
"If you're willing to put up with some bugs, then join us in this brave new world," wrote Scott Hanselman, a principal program and community manager for Microsoft, on his personal blog Wednesday. "We're calling today's release version 0.5."
Hanselman had long advocated taking Windows Live Writer open-source, and in June said that Microsoft had okayed the move.
"There was a lot involved both legally and technically as we were breaking new ground for Microsoft," added Hanselman. "Consider this. We've successfully open sourced a previously completely proprietary piece of Windows software that shipped as part of Windows Live Essentials. This software was used by millions and contained code as old as a decade or more. Persistence pays off."
The project ended up under the .Net Foundation umbrella, which characterizes itself as "an independent organization to foster open development and collaboration around the .Net ecosystem." .Net is a Microsoft development framework that is used almost exclusively on Windows.
In a post to the .Net Foundation's own blog, Rob Dolin, a Microsoft senior program manager, called for volunteers to help develop and test Open Live Writer. "Continued improvements are dependent on volunteers," Dolin said, pointing those interested in contributing to the code on GitHub.
Windows Live Writer, a spiritual if not literal predecessor to Open Live Writer, debuted in 2007 alongside Windows Vista, and was part of Windows Live Essentials, a bundle that included several now-defunct programs, such as Mail, Messenger, Movie Maker, Photo Gallery and SkyDrive. Live Writer was last updated in 2012, shortly after Microsoft retired the Live brand.
But Live Writer -- a what-you-see-is-what-you-get tool for writing and posting blogs to a plethora of platforms, including Blogger and WordPress -- has retained a devoted and vocal cadre of followers.
Open Live Writer is intended to scratch that itch.
As the app stands now in version 0.5, it can be used to publish to Wordpress.com, hosted Wordpress blogs, and Google's Blogger.
Currently, Open Live Writer supports Windows 10, Windows 8 and Windows 7. The latter two, however, may be temporary. In a FAQ, the group said, "We hope to support Windows 7 and Windows 8 for a while at least," in an answer to a question whether the app works on older editions of Microsoft's OS.
A partial port to Apple's OS X, as well as to Linux, may be possible, the group added, but would require significant time and effort by volunteers since much of the code relies on Windows-specific APIs (application programming interfaces).
The Open Live Writer roadmap has been posted to GitHub. By the 1.0 release, the group hopes to add support for the TypePad and LiveJournal blogging platforms.
Open Live Writer can be run side-by-side the original Windows Live Writer 2012. The latter can still be downloaded from Microsoft's website as part of Windows Essentials.