A new update to the U.S. standard "Geopolitical Entities and Codes" has been published. It shows substantive changes for Fiji divisions and provinces, India, Ireland, Lithuania counties and municipalities, Montenegro, Panama, and Solomon Islands.
The similar but distinct U.S. standard "Geopolitical Entities, Names, and Codes," Edition 2, was issued on 2014-03-31. It matches ISO 3166-2 in many cases, but it lists some subdivisions that aren't covered by ISO. There are differences in Bermuda, Chad, Congo (Brazzaville), Côte d'Ivoire, Cuba, Dominican Republic, Indonesia, Iran, Kenya, Kyrgyzstan, Laos, Montserrat, Namibia, Oman, Papua New Guinea, Saint Lucia, South Korea, Taiwan, Tajikistan, Tanzania, Uganda, United Kingdom, and Zambia.