AFAIK, both versions are 125B. I got mine shortly after Mike started listing them and mine says 125B and they have three white motor wires. However, the current ones I see have different colored "neon" motor wires, so I assume those are the "new" ones?
Either way, the ESC is listed as capable of 6s, so if it doesn't, you can get Quark/S&T support to replace or fix it.