This announcement doesn't say anything about versioning for the underlying mozilla platform (which moves from 1.92 to 2.0 between Firefox 3.6 and 4.0). The vers

This announcement doesn't say anything about versioning for the underlying mozilla platform (which moves from 1.92 to 2.0 between Firefox 3.6 and 4.0). The versioning for the platform only changes when the api changes and breaks binary compatibility for people who use binary components in extensions. Authors writing pure JavaScript extensions can code them to be compatible across multiple Firefox versions.