I'm using rhomobile suite 5.4 and I've also tried 18.104.22.168 from tau-technologies.
Both versions crash the applications when this code is executed:
beeperProps = Hash.new
beeperProps['frequency'] = 2000
beeperProps['volume'] = 2
beeperProps['duration'] = 500
# This code crashes Zebra TC75 Lollipop
It works on android KitKat (4.4.X).
Hopefully this is something fixable.