Mozilla is expected to spin out a complete version of Firefox 3.5 tomorrow, more than six months on from when it had originally planned to release the browser.

A company rep confirmed on Friday that 30 June had been earmarked for the day Firefox 3.5 would be shipped.

Firefox 3.1 morphed into 3.5 earlier this year. Mozilla made the switch in part as an acknowledgment of lengthy delays to the browser's release, all of which meant it had undergone a sufficient degree of development to allow for a new version number to be added.

The number of new features packed into the imminent version of Internet Explorer’s closest rival meant it was necessary to reflect those changes in the name, said Mozilla’s engineering veep Mike Shaver back in April.

"The increase in scope represented by TraceMonkey and Private Browsing, plus the sheer volume of work that's gone into everything from video and layout to places and the plugin service make it a larger increment than we believe is reasonable to label 3.1," he said at the time.

Originally, Mozilla had slated December last year as the release date for Firefox 3.5 nee 3.1. But the browser's development process was hit by several delays due to show-stopping bugs, mostly found in the open source outfit's JavaScript engine, which pushed back the deadline several times. ®