I am confused about SOAP namespaces

I am learning about SOAP implementation and have become somewhat confused regarding the appropriate namespace URI for a SOAP 1.2 Envelope.

The w3c specification for SOAP refers to the "http://www.w3.org/2003/05/soap-envelope" namespace. However, I have seen other examples that refer to the "http://schemas.xmlsoap.org/soap/envelope/" namespace.

It seems to me that one or the other namespace should be used. Which of these two is the correct namespace URI to use?

It is related to the SOAP version. SOAP 1.2 uses http://www.w3.org/2003/05/soap-envelope for the namespace and SOAP 1.1 uses http://schemas.xmlsoap.org/soap/envelope/.

For reference, see http://www.w3.org/TR/soap/ and look at the envelope section in the different version specs.

Also, you can browse to each of those envelope URLs and check the version number to see exactly which version of the spec you are using.