Mozilla is moving to a four-week release cycle for teh Firefox browser, in order to bring you new features more quickly.
Starting Q1 2020, Mozilla plans to ship a major Firefox release every 4 weeks. Firefox ESR release cadence (Extended Support Release for the enterprise) will remain the same. In the years to come, Mozilla anticipates a major ESR release every 12 months with 3 months support overlap between new ESR and end-of-life of previous ESR. The next two major ESR releases will be ~June 2020 and ~June 2021.
"Shorter release cycles provide greater flexibility to support product planning and priority changes due to business or market requirements. With four-week cycles, we can be more agile and ship features faster, while applying the same rigor and due diligence needed for a high-quality and stable release. Also, we put new features and implementation of new Web APIs into the hands of developers more quickly," according to Mozilla.
Currently, Mozilla typically ships a major Firefox browser (Desktop and Android) release every 6 to 8 weeks.