ID:176443 Devices selected for migration have different speed grades -- frequency limits are checked only for current device, not all devices

CAUSE: You specified migration devices for the design, but the target devices have different speed grades. The Fitter checks the frequency limits only for the current device, not all devices. All devices specified for migration must have the same speed grade.

ACTION: Specify the same speed grade for all devices, or make sure that the design does not exceed the frequency limits for the devices with the slowest speed grade.