It's been just about six weeks since the last Firefox release and version 11 was scheduled to be released tomorrow, but Mozilla just announced that users will have to wait a little bit longer for the next version of the popular browser. Johnathan Nightingale, the senior director of Firefox engineers, explains that there are two reasons for this schedule change. 1) Microsoft's monthly Patch Tuesday would coincide with the release of Firefox 11 and, according to Mozilla, those updates have "interacted badly" with its own updates before, and 2) Mozilla is waiting for a report from the Zero Day Initiative (ZDI) about a security vulnerability that "may affect this new version of Firefox."
This security report is due later today, but the Mozilla team obviously still has to evaluate the vulnerability and, if necessary, patch Firefox 11 before releasing it. Nightingale still assumes that Firefox 11 will be released later this week.
This is the first time Mozilla had to postpone a Firefox release since it moved to its rapid-release schedule last year. The last major delay came before the release of Firefox 4, but this was also the last release before Mozilla changed its development cycle.
If you still want to get an early look at Firefox 11, though, you can always download the latest beta version here.