Download Android App Firefox Browser: fast, private & safe web browser old version .apk ❤️. If You Want To Download Firefox Browser: fast, private & safe web browser old version for your Android device, you should do easy instruction. You need go to the Settings menu and allow, installing .apk files from Unknown Resources. After that, you could calmly download all .apk files from APK4K, and confidently install it on your AndroidOS Device.