How to Enable APRS on The AT-D878UV

Some radios like Kenwood and Yaesu can send messages (analog) to other APRS radios and also can send a message from the radio to a cell phone. For example on the radio
TO: SMSGTE
@N1KK-5 Hello Ken

This message would show up on a APRS analog radio.
replacing N1KK-5 with a cell phone number would send the message to the cell phone.
Replying from the cell phone would send it back to the APRS radio. Can this feature be added now or can it be requested to add the feature?
Ken