Firmware for PS6100x and PS4000

Hello -

My current environment has a Dell PS4000 at Firmware v6.0.5 connected to a Dell M1000e with VMware 5.0.

We recently ordered a Dell FX2. We have a PS6100x we are hoping to connect to the FX2. The Firmware on the PS6100x is v7.0.4.

Can the PS6100x be connected to the FX2?

If yes, can these 2 SANs be added to the same Configuration Group and Storage Pool at their current Firmware Version's to do a migration (vMotion) of VMs from the PS4000 to the PS61000x (VMware 5.5) or do we need to upgrade the Firmware to v7.1.2 on both?

Thanks,