See: Description
MIL-STD 2525b implementation is based on MIL-STD 2525b w/Change 2 Common Warfighting Symbology, DOD, March 2007.
MIL-STD 2525c implementation is based on MIL-STD 2525c Common Warfighting Symbology, DOD, November 2008.
MIL-STD 2525d implementation is based on MIL-STD 2525d Joint Military Symbology, DOD, June 2014.