Just picked up a Drobo B810n. Filled it up with eight 6tb WD RED drives. After installing the latest firmware, the Drobo Dashboard tells me “The set of disks you have inserted are incompatible with the firmware running on your Drobo device. There may be an update that allows you to use these disks. Please make sure that your Drobo device is using the latest firmware.”
I have verified that I am indeed on the latest firmware, 3.5.12.
These drives worked perfectly in the Drobo B800fs I am upgrading from.