The next major update for Firefox, v3.1, will instead become v3.5, says Mozilla's director for the browser, Mike Beltzner. Developers have allegedly complained that the v3.1 designation does not reflect the number of changes in the browser, which is already at v3.0.7 and yet missing components key to the former v3.1. Central is the addition of TraceMonkey, an engine which allows native code compilation within Mozilla's JavaScript technology.

The update will also incorporate a Private Browsing mode, enabling users to browse websites without leaving a record of where they have been. Beltzner further hopes Firefox will gain extra attention with the new numbering, though he observes that the shift to v3.5 will bring no features not originally planned for v3.1. The new designation will take effect with beta 4 of the update, scheduled to be uploaded April 14th. Firefox 3.1 beta 3 is still scheduled to go online on Thursday.