Add a setting to enable/disable vibration either on calls or messages
As far as I know, a user can either enable sound and vibration or disable both of them (not within the app, but by changing general mobile profiles). What happens if a user wants to recieve notifications with just only sound (no vibration at all)?
From the Android support, they say that each app should provide a way to configure vibration, so what do you think of adding that setting to the app? Ideally there should be one setting for messages (also for sound which doesn't exist for now) and another one for calls. But it could be a good approach to have at least one general setting to configure vibration within the app.
I would suggest adding it next to the ringtone setting.