Blizzard
Beginning May 18 with the launch of the Burning Crusade Classic pre-expansion patch, WoW Classic players will choose whether to progress each of their characters to Burning Crusade Classic with the rest of their realm, or continue playing the original WoW Classic content on brand-new Classic Era realms also launching that day. Players who wish to experience the best of both worlds will be able to use the optional character cloning service (available May 18, $35 per character), which will allow them to continue playing a copy of an existing character on a Classic Era realm while also advancing into Burning Crusade Classic.