From The Truth About Guns:

The most notable changes are the inclusion of the firearm information at the top of page one instead of page three, the change of “county” to “county/parish/borough,” and the addition of “non-binary” to the gender.
There are, of course, other changes but they are not as significant as these and they apply mostly to the FFLs.  There is a full breakdown of each change, and what it means for FFLs, in the RocketFFL compliance program.