Android app needs to tell participants if they are using an out of date app version.

[biblicabeebli]

After the removal from the Google Play store we need to research options on telling the participant that they should update the app.

I have no idea if there are libraries for this, there probably are.

(provided the signing key is unchanged an apk file update to beiwe will not clear app data.)

[biblicabeebli]

• We could do [Android, iOS] Send push notifications to out-of-date android app users starting with version 3.6.0` #97 but I still need to see if there is any way to do this automatically.