APP-6A was promulgated in December 1999. The NATO standardization agreement that covers APP-6A is STANAG 2019 (edition 4), promulgated in December 2000. APP-6A replaced APP-6 (last version, July 1986), which had been promulgated in November 1984 (edition 3 of STANAG 2019 covered APP-6), and was replaced in turn by Joint Symbology APP-6(B) (APP-6B) in 2008 (STANAG 2019 edition 5, June 2008) and NATO Joint Military Symbology APP-6(C) (APP-6C) in 2011 (STANAG 2019 edition 6, May 2011).
