Mozilla kills Firefox Aurora channel, builds will move directly from Nightly to Beta

Mozilla today announced plans to kill the Firefox Aurora channel on April 18, six years after it was first introduced in April 2011. The company shared that “Aurora was not meeting our expectations as a first stabilization channel” and that the decision will streamline its browser’s release process and bring stable new features to users and developers faster.

The Firefox Aurora channel sat between the Nightly and Beta channels. Until now, Firefox development started with Nightly, which consists of the latest Firefox code packaged up every night for bleeding-edge testers, and was then followed by Aurora, which includes everything that is labeled as “experimental,” then Beta, and then finally the release channel for the broader public.

Going forward, builds will move from Nightly to Beta to Release. The Firefox Developer Edition, which the company calls “the first browser created specifically for developers,” will be based on the Beta channel instead of Aurora. Developer Edition users should keep their existing profile, themes, tools, preferences, and “should not experience any disruption,” Mozilla promises.

More specifically, here is how the change will occur (the current channels are Firefox 52 in Release, Firefox 53 in Beta, Firefox 54 in Aurora, and Firefox 55 in Nightly):

On April 18, code for Firefox 54 will move from Aurora to Beta as usual, while Firefox 55 will remain on Nightly for a second cycle in a row (a total of 14 weeks). On the next merge day, June 12, Firefox 55 will move directly from Nightly to Beta. Between April and June, Firefox Aurora on Desktop (54) will continue to receive updates for critical security issues and the Aurora and Developer Edition populations will be migrated to the Beta update channel. On Android, Aurora users will be migrated to Nightly.

Mozilla argues that this will clarify the Firefox channels for both users. Those who want to try experimental features will go with the Nightly channel, developers will get more stable builds in the Developer Edition, and everyone will see faster release cycles for platform features.

The reality is that Mozilla is likely looking to consolidate resources. The company claims it has “more modern processes underlying our train model, and believe we can deliver feature-rich, stable products without the additional 6-8 week Aurora phase.” The staged rollout mechanism that the company uses with the Release channel will be used for the first weeks of Beta, and a new feature will merge from Nightly to Beta only when it’s deemed ready based on pre-established criteria determined by the Firefox engineering, product, and product integrity teams.

The company promises the following new tools and processes that will ensure removing the Aurora channel will not lead to unstable releases:

• Static analyzers integrated as part of the workflow, in order to detect issues during the review phase. They will be able to identify potential defects while minimizing technical debt.
• Code coverage results will be used to analyze the quality of the test-suite and the risk introduced by the change.
• The ability to identify potential risks carried by changes before they even land by correlating various data sources (VCS, Bugzilla, etc.) in order to identify functions where a modification is more likely to induce a regression.
• Monitoring crash rates, QE’s sign offs, telemetry data and new regressions to determine overall Nightly quality and feature readiness to merge to Beta.

This all sounds great on paper, but time will tell if it works better in practice. Google continues to have four Chrome release channels (which Mozilla “borrowed” for its Firefox development cycle): Stable, Beta, Dev, and Canary.