RE4 2TB WD2003FYYS firmware revisions

 I have various RE4 2TB WD2003FYYS dirives with firmware revisions 01.01D01, 01.01D02 and 01.01DB2. I am in the process of upgrading all the 01.01D01 ones to 01.01D02. The 01.01D02  file is dated 6-15-2011 and  was sent to me by WD support in Apr 2012. I recently purchased 5 disks with manufacture date of Nov 2011 and they came with 01.01DB2. Does the B mean a beta version?

Does anyone know which is the latest and/or version  01.01D02 or 01.01DB2?

Not sure what the “B” means, but if the drives were manufactured on 11/2011, the firmware must be newer than the one released on 06/2011.  I suggest you to contact WD Support to verify this information.