Firefox is already one of the most compelling browsers in the industry, but Mozilla has never been content to leave well-enough alone. The company rolls out regular updates for the browser and experiments with interesting new features via its "Test Pilot" program. However, even Mozilla's relatively-fast two-month update pace doesn't seem to be enough for the company's leadership team.
Starting in Q1 2020, Mozilla will move Firefox over to a 4-week release cycle, meaning users should expect bug fixes, fresh features, or other changes on a monthly basis. This is a significantly speedier timeframe than Mozilla is used to, so it remains to be seen whether or not the company will be able to adapt to it seamlessly. With that said, the team does seem fairly confident in their abilities -- apparently, this faster release cycle will pave the way for "more agile" feature shipment; without compromising on update stability.
Mozilla says it won't be able to accomplish this task without the help of its users. Moving forward, feedback provided by Firefox Beta or Developer testers will be "essential." As a result, these users can expect to see much more frequent Beta builds.
Another important aspect of Mozilla's new four-week release cycle will be slower rollouts for "high-risk" feature updates. This means that if such an update is scheduled for release on a specific day, its actual launch may be staggered quite a bit -- some users may receive it right away, others might receive it over several days. This allows Mozilla to quickly halt the update's rollout if critical issues are discovered, with only a minimal impact to its wider userbase.
The first update set to be part of this monthly release cycle is version 72, which we can expect to see on January 7. Version 73 will release on February 11, and updates will continue at a similar pace well into late 2020.