The Mozilla Foundation has abandoned plans to release a version of its popular Firefox web browser for the Windows 8 Modern UI, just days before it was scheduled for release.

The dual personality nature of Windows 8 and its more recent successor Windows 8.1 splits the development experience in twain: applications are either written with the legacy Desktop in mind, or the new touch-centric Modern UI. While the legacy build of Firefox works just fine, the Foundation had planned to release a Modern UI version as well with the non-profit group's vice president Jonathan Nightingale claiming 'it looked like the next battleground for the web.'

Amid fears that third-party browsers would be locked out of the Modern UI entirely, Nightingale set up a development team in late 2012 to port Firefox to what was formerly known as the Metro UI. Now, after more than a year of development, that port is being canned just days before its planned release date.

'In the months since, as the team built and tested and refined the product, we’ve been watching Metro’s adoption. From what we can see, it’s pretty flat,' Nightingale explained in a formal blog post 'On any given day we have, for instance, millions of people testing pre-release versions of Firefox desktop, but we’ve never seen more than 1000 active daily users in the Metro environment.

'This leaves us with a hard choice. We could ship it, but it means doing so without much real-world testing. That’s going to mean lots of bugs discovered in the field, requiring a lot of follow up engineering, design, and QA effort. To ship it without doing that follow up work is not an option. If we release a product, we maintain it through end of life. When I talk about the need to pick our battles, this feels like a bad one to pick: significant investment and low impact.

'Instead, we pull it. This opens up the risk that Metro might take off tomorrow and we’d have to scramble to catch back up, but that’s a better risk for us to take than the real costs of investment in a platform our users have shown little sign of adopting,
' Nightingale concluded.

As with the company's other products, Firefox for the Modern UI is open-source, with the code remaining available on the official website for anyone who wants to pick up where Mozilla left off and develop the browser port themselves.