WSDL 1.2 is the planned successor to WSDL 1.1. At the time of this writing, WSDL 1.2 is still in 'working draft' mode. Most SOAP Servers currently do not support the 1.2 version.

Improvements over WSDL 1.1 include:

• Language clarifications
• Support for W3C Recommendations, including XML Schemas and XML Information Set
• A conceptual framework approach to define the description components
• The removal of unnecessary and non-interoperable features
• A better definition of the HTTP 1.1 binding.

Here is the WSDL 1.2 specification.

Here is the WSDL 1.2 bindings specification.

See: WSDL, WSDL 1.0, WSDL 1.1