There are no plans to discontinue the UNO R3, as the projected demand remains strong. To offer a consistent developer experience between the 8-bit UNO R3 and 32-bit UNO R4, significant efforts are ...

We have been working hard to make sure the UNO R4 is highly retrocompatible with code written for UNO R3, including tutorials and libraries.” For more information about the Arduino UNO R4 check ...