Checker for RCS description

1.What's the RCS?
Rich Communication Services (RCS) is a communication protocol between mobile telephone carriers and between phone and carrier, aiming at replacing SMS messages with a text-message system that is richer, provides phonebook polling (for service discovery), and can transmit in-call multimedia.
2.What's the Checker for RCS?
There a widget for checking RCS setting where there is not RCS update.