Apple are usually careful not to announce new hardware until it's just about ready to ship (with the occasional exception coughAirPowercough), but in this case (assuming the report is correct) I suspect they'll be making an exception. Four months between announcing Apple Silicon and the first hardware hitting retail seems far too short for developers to properly prepare. So I'm guessing that this will be an announcement well in advance of hardware shipping, maybe early next year, to give developers a clear target to aim for (both a hardware target and a calendar target).