This is hardcode, just create a new filed into Portal table with a migration and script it into basicpackethandler like this:
Code:
if (portal.RequiredItem != 0)
{
if (Session.Character.Inventory.GetAllItems().All(i => i.ItemVNum != portal.RequiredItem))
{
Session.SendPacket(UserInterfaceHelper.GenerateMsg ("You need to craft the key of Prestige Lobby first or reach Prestige 1!", 10));
return;
}
}
without else because you already have the ChangeMap method