You can upgrade anytime but you cannot downgrade your account. In order to downgrade please contact our support.
In order for us to "change" the stream type, a whole new account has to be created. There are no upgrade options when it comes to streams. Once you choose a stream that is the stream you have. If you want to change or upgrade to a different version (shoutcast v1.9 to shoutcast v2.0 for example), a new stream account has to be created in order to make the upgrade. Please contact us for more info.