Is the country México or Méjico?

Question

Is the name of the country south of the United States spelled México or Méjico? Which is the official name of the country in English and Spanish? When is each version used?

Answer 1

You can see from the official Mexican seal, that the official, modern name is spelled with an X and not a J.

(Source: Wikipedia)

Furthermore, from @Richard's answer to another question is this article about the use of x versus j and the change that took place.