xbee module Hw Ver

I’m using a couple of xbee znet 2.5 series2 modules, in AT mode, with one coordinator and one end_device.
With hardware version 1942 all it’s ok. If I use a coordinator with hardware version 1941 they don’t comunicate.
What is the problem?
Where is documented the difference between the two hardware release?

The hardware version difference shouldn’t matter.

If you have multiple coordinators, are they operating on different channels? Is the end device on the same channel (and PAN ID) as the coordinator with hardware version 1941?