What is the Minimum Android OS for RoamBABY?

What is the Minimum Android OS for ROAMbaby ?Note: ROAMbaby is an Android smartphone which is offered by the Internet Telephone Carrier, BabyTel. With RoamBaby,
you can make or receive calls over your carrier’s data network or over Wi-Fi without using your expensive cellular minutes in Canada and the U.S.

The ROAMbaby App works just like your Android phone, and uses the same phone contacts. And, works on all Android phones and tablets with Android 1.6
or higher.

For business and personal accounts, contact Atlantic Webs Customer Service or signup at http://ebill.atlanticwebs.com.

The ROAMbaby app is available from the Google Play website.