Back in December, it was announced Firefox 3 would be moving away from the traditional four-part numbering (ex Fx 2.0.0.*) to a three-part numbering (Fx 3.0.*). However at that time the numbering scheme was not yet supported on addons.mozilla.org (AMO). With RC of Firefox 3.0 (3.0Pre) coming available (on Minefield Trunk) AMO has made modifications to accept the new production version numbering.

• Firefox 2: 2.0 – 2.0.0.*
• Firefox 3: 3.0 – 3.0.* (Note: that with Firefox 3, it’s a three part version number)

News Source: Basil’s Bodacious Blog