Hi, yes it is possible and 100% legal to use the Firefox APKs available at archive.mozilla.org. About 4 years ago, it was discussed that only saving the APKs on the Google Play Store was not enough. As there needs to be more availability for people who want to directly download the APKs from Mozilla directly for testing and personal use and to avoid app stores. So they started uploading the APKs to both Github and archive.mozilla.org. Please feel free to use any of the builds you find there. A lot of our testers use APKs there to hunt down bugs using builds with daily timestamps. Also "Fenix" is just the codename for Firefox for Android. They are exactly the same thing. Older Github APK releases (I think all new Firefox APKs are now saved at archive.mozilla.org): https://github.com/mozilla-mobile/firefox-android/releases Current Fenix releases: https://ftp.mozilla.org/pub/fenix/releases/ Nightly builds (For testers to test a new build of Firefox every day): https://ftp.mozilla.org/pub/fenix/nightly/2025/ Candidate builds - Beta builds that are very close to being released as the main release: https://ftp.mozilla.org/pub/fenix/candidates/ The most common architecture for phones: 2025-03-14-21-11-55-fenix-138.0a1-android-'''arm64-v8a''' 2025-03-14-21-11-55-fenix-138.0a1-android-'''armeabi-v7a''' If those don't work, there are other versions you can try: https://ftp.mozilla.org/pub/fenix/nightly/2025/03/2025-03-14-21-11-55-fenix-138.0a1-android-x86/ https://ftp.mozilla.org/pub/fenix/nightly/2025/03/2025-03-14-21-11-55-fenix-138.0a1-android-x86_64/