It was told in some of articles. Postmans using phones together with bluetooth POS to recieve payments for different kinds of citizen payment services. And yes, camera is used to scan different barcodes to receive payment for certain invoice, rather than filling it's number manually.

RussianPost is more than postal service. It's the only people who can go to your old mother home, receive payments for services and give monthly pension for her, so she doesn't need to go some kilometers to nearest bank or something else.