You will see this critical warning beginning in the Quartus® II software version 12.0 anytime you use ALTLVDS receivers in Stratix® III, Stratix IV, Arria® II, HardCopy® III, or HardCopy IV devices. The critical warning is issued even if your ALTLVDS instance does not use DPA or soft-CDR enabled channels. This is to notify you that there are placement restrictions in the event you decide to enable DPA or soft-CDR mode in the future.
Refer to the placement restrictions detailed in the related solution below to see if your design is affected.
This critical warning can be ignored if the design does not use DPA or soft-CDR enabled receiver channels.