When I try to find my phone the phone displays a window with a huge FOUND button but remains silent. Desktop app is v0.8 (ubuntu 16.04), phone app is v1.8.2 (latest from f-droid). Samsung S5 with android 6.0.1, all sounds levels (ringtone, media, notification, system) are at reasonably high values.
https://cgit.kde.org/kdeconnect-android.git/commit/?id=2cd7d4b7a99aa0073e1a29627b5b10628fa840fd