First off there is no Thunderbird for Android. Any app that is claiming to be is malware. You can try K-9 email an open source email client for Android instead. By default we suggest users use Google Play to get Firefox for Android, https://play.google.com/store/apps/details?id=org.mozilla.firefox If you are completely avoiding any Google services we suggest the Firefox Aurora build as it has a self updater. It can be downloaded from https://www.mozilla.org/en-US/firefox/channel/#aurora You can install the build buy using the Android SDK on your desktop or copying the apk to your phone and using a file browser such as OI file manager to locate the file and launch the installer. You will need to change the Android OS setting for installing apps from 'Unknown sources'.