Xbee OEM RF Module series 1 vs series 2

is it ok to used?? my xbee from series 1 which is my coordinator and the rest will be end device xbee series 2?
the series 1 has Xb24 802.15.4 version 10CD while the end device xbee has XB24-ZB?

The two rf module/firmware types are not compatible.