If models or textures get exchanged completely, all chars of the same race will change (as happened to e.g. Dermorians and female Nolthrirs and dwarfs).
But if only a few variants got added, the old chars can probably not be changed much by a Game Master. My Dermorian char once lost his green face tattoo during an upgrade and was not able to get it back.
Possibly the only trait which is changeable by Game Masters is the color and maybe style of head hair (not the whole Enkidukai fur or Kran skin; and Esorono's gray skin was probably a testing exception). Search for "Madame Snorial" in this forum and try to ask for her return.
