CorelDraw x6 and CorelDraw x7 version numbers in the CDR file (binary or hex)

In previous version of CorelDraw (x5 and before) you could open the CDR file in notepad and look for CDR?vrsn to find out which CorelDraw version created the file.

CDR9vrsn = CorelDraw 9
CDRAvrsn = CorelDraw 10
CDRBvrsn = CorelDraw 11
CDRCvrsn = CorelDraw x2 (12)
CDRDvrsn = CorelDraw x3 (13)
CDREvrsn = CorelDraw x4 (14)
CDRFvrsn = CorelDraw x5 (15)

But now in CorelDraw x6 (16) and CorelDraw x7 (17) the CDR?vrsn no longer exists in the CDR file.  How do you tell what version a CDR file was created in (without the CorelDraw app) for x6 and x7 versions?