Players must have the previous level of development before applying and upgrading a development trait.
Normal -> Star -> Superstar -> X-Factor

If player is Star Development, you may purchase Superstar and upgrade the trait.
(Player can’t jump from Normal to Superstar or Star to X-Factor.)
(Superstar’s and X-Factors limited to 2 per season.)
(Dev’s purchased for Legends & T2E Superstars count for limit)