Responding to comments that the TraceMonkey engine is a very important addition, a Mozilla engineer says the new Firefox should make that clearer.
"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 .1," wrote Shaver. "3.5 will help set expectations better about the amount of awesome that's packed into Shiretoko, and we expect uptake help from that as well."
This means that version identifiers will have to be adjusted starting with the 3.5 beta. What had at various times been considered the "4.0 alpha" and the "3.5 alpha" (code-name "Minefield") will be given the temporary designation 3.6, although Shaver says not to treat 3.6 as that version's final designation just yet.