Officially we only support Android 6.0 or higher (though some Android 5.0 phones may work). You may want to see if you can use a friend or family member's phone for the setup. After the setup, you can do most everything on the headset itself (aside from pairing new controllers and a few other things).
I have the same issue...kind of inconvenient to have to ask someone to come over to my place so that I can use their phone..then tell them to come back a week later when I want to pair a new controller or something...