Mullvad Browser Alpha moves to Firefox Rapid Release and adds Linux ARM support

26 марта 2026 г. News Browser

Starting with 16.0a1 alpha release, Mullvad Browser Alpha is based on the Firefox Rapid Release channel rather than the Extended Support Release (ESR). The alpha release is now available on Linux ARM.

Every year, to correspond with a new Firefox ESR release, there would be many months of stressful work in order to catch up with a full years worth of Firefox changes.

Tor Project is now experimenting with a different approach to releases, spreading the workload of the annual ESR transition throughout the year. To this end, Mullvad Browser Alpha has transitioned to the Firefox Rapid Release channel, while the Stable channel remains on Firefox ESR.

What this means for Mullvad Browser Stable users

We have previously had two feature releases per year: one in Q2 and one in late Q3. With this new development model, we expect to have only one major feature release per year.

What this means for Mullvad Browser Alpha users

This shift brings several changes that users of the Alpha channel should be aware of:

Quicker Access to Features: Users will receive new upstream features from Mozilla shortly after they are introduced, rather than waiting for the next major ESR update.
Potentially Less Secure and Private: Because features will be shipped more rapidly, the likelihood of encountering upstream bugs that could impact security and privacy increases. As always, Alpha builds are intended for testing purposes. If you are an at-risk user or require a reliably working browser, you should use the Stable channel.
A Less Predictable Release Cadence: Sometimes the intersection of upstream changes, our build system, and our patches introduce rather difficult problems for us to solve. It may take longer than the available four week window of time between scheduled Rapid Release versions to implement fixes.

For a comprehensive explanation of the technical rationale, you can read the full announcement on the Tor Project’s blog: The Future of Tor Browser Alpha.

Availability on Linux ARM

We are also happy to announce Mullvad Browser Alpha is now available for ARM platforms on Linux. You can download it manually via our website or install it directly using our RPM and DEB repositories.

Become a tester!

Now is a great time to become a Mullvad Browser Alpha tester! However, if you are at risk or need strong anonymity, please stick with Mullvad Browser Stable.