Which generation of the SuperSting™ will the SSM Android App work with?

Short Answer: Only the SuperSting™ Wifi.

Long Answer: The SSM Android App is only supported with the SuperSting™ Wi-Fi resistivity instrument. If your instrument faceplate says "Wi-Fi" then it is compatible with the SSM Android App. If you don't see the word "Wi-Fi" then your SuperSting™ will not operate with the SSM Android App.