There are 27 legal versions of the USA flag that have evolved throughout the history of the United States. By law, a star is added to the U.S. Flag on the 4th of July following the admission of the State(s) to the Union. No version of the U.S. Flag ever becomes obsolete, and any version can be flown at any time. 
 
49 Star - States Admitted to the Union for this flag: AK