Is it possible to communicate between nRF51822 and device that is using older bluetooth version (2,3) ?
No.
nRF5x are Bluetooth Smart (aka Low Energy) only - and that is (at least) v4.0 of Bluetooth.
No, it is not possible. Bluetooth Low Energy is very different from Classic Bluetooth (and in fact started off as a totally independant standard, Wibree).
