Why is the IdToken a String and not a class?

Well originally it was a class, but later on it changed to a String: https://github.com/ChargeTimeEU/Java-OCA-OCPP/commit/fc62dc12d5b141658e37ab5b08f45d141cd9397a

Why did we do this?

Emil pointed out that the WSDL defined the IdToken as a String. This didn't concur with the specs, that defined it as a class.

It turns out that the definition in the original spec was wrong, which was addressed in an errata. IdToken should have been a type.