Good day,
we recently had the pleasure to replace a UR10 (went very well and easy). Everbody kept saying that you need to keep the Robot in combination with the Controller in terms of serial number. But why is that? Ss the calibration Data stored in the Controller? Could you in that case just update the Software Version so its stored in the Arm (5.8.0 i believe)? Cant seem to find anything online about it 
Thanks everybody!
The calibration data is sort of stored in the controller. From 5.9.0 (as far as I remember) on the e-series robots, the calibrations were also saved in the joints. But I am not entirely sure still how it works when using another controller.
I would definitely advise you to use the corresponding Polyscope. So it’s not as much a question of using the same controller, but more of using the corresponding memory card. If you want to use the old e-series controller with your new e-series robot arm (I assume it’s all e-series), you can just move the memory card from the new system to the old system. 
Then you can transfer the program files separately.