Default text messaging for Lollipop

[AC Question]

I just bought a Fitbit tracker that's supposed to vibrate and show me text messages but all it keeps doing is just telling me I have a new message. It's supposed to say who sent it and what it says but it doesn't. I've been working with Fitbit to try and get this fixed and they asked me to be sure "show preview" was clicked under the messaging app but I don't see messaging listed as an app. Was I supposed to change my messaging app when I upgraded to Lollipop? If so, what is the default app for Lollipop?