Because Moxie doesn't want it to be[1]. It should be noted though than you can download just the APK from their website[2] and it supports auto-updating. [1]:

Because Moxie doesn't want it to be[1]. It should be noted though than you can download just the APK from their website[2] and it supports auto-updating. [1]: https://github.com/signalapp/Signal-Android/issues/127 https://github.com/signalapp/Signal-Android/issues/127 [2]: https://signal.org/android/apk/ https://signal.org/android/apk/