Upgrade existing Amazon FireTV App project with improved features, including In-App Purchasing.

Need highly experienced Amazon FireTV development specialist to: (1) upgrade/modify existing FireTV App built entirely in Android Studio; (2) assist creator with developing in-app purchase functionality (subscription) using latest Amazon In-App Purchasing API and the Appstore SDK; (3) assist creator with installing working copy of final App in Android Studio at creator's office in Los Angeles. This is NOT a mobile App so mobile App development experience is not on target.