Whether RCS can be used is affected by many aspects such as mobile phone equipment, operators, regions and user settings. It is impossible to determine whether the recipient supports RCS based on the number format alone.
The ordinary number list lacks RCS activation status
A valid format does not mean that RCS messages can be received
There are differences in RCS coverage among different operators
The RCS status may change after the user replaces the device.
Blind sending increases failure fallback and communication costs
Manually confirming numbers one by one is very inefficient
