ANSI 117.1 is a standard for accessibility in buildings and is referenced by the International Building Code. The two most recent versions were published in 2003 and 2009. Technically ANSI 117.1 is only a standard but because it is referenced by the building code it becomes part of the code.
Most jurisdictions are either using the 2009 or 2012 International Building Code (IBC). If the jurisdiction has adopted the 2009 IBC then we refer to the 2003 version of ANSI 117.1. This is because the 2009 version of ANSI 117.1 was not finalized when the 2009 IBC was published. If the jurisdiction has adopted the 2012 IBC then we can refer to the 2009 version of ANSI 117.1.
There are some differences in the 2003 and 2009 versions of ANSI 117.1 so it is important to consider which version you should be using. For example in the 2003 version, primary entrance doors into Type A and B dwelling units only need to be accessible from the exterior side. But in the 2009 version, primary entrance doors need to be accessible from both the unit side and the exterior side of the dwelling unit.