Mozilla is blaming slow progress as the reason for the delay.
Late last month, Mozilla's Firefox planning meeting revealed that the company intended to launch a Metro UI version of its browser on December 10, 2013. In fact, the company already had Metro Firefox available in the Nightly channel and was asking Windows 8 users to help fine-tune it before its merger with the Aurora channel this week. However, it seems those hoping to see the browser go public in December will have to wait a bit longer.
PCWorld reports that the Windows 8 version of Firefox won't be available until January 2014. The publication cites Mozilla as saying slower-than-expected progress has pushed the release back by more than a month.
"The goal of the Metro Preview Release is to gather feedback and defects from the larger Aurora community," Mozilla is quoted as saying in planning meeting notes. "Whether or not the Metro Preview Release will graduate from Aurora to Beta and Release channels is still to be determined. At a minimum, it should significantly increase the number of testers and feedback."
So when can Windows 8 users expect the touch-based browser to be publicly available? According to Mozilla, the 'decrease in average team velocity' over the previous two iterations positions things for a Firefox 27 release on January 21, 2014. This would put the public release at almost two years after Mozilla first verbalized plans to build a Windows 8 version of Firefox (in March 2012).