SOAP 1.2 is the intended successor to SOAP 1.1. The primary differences between 1.1 and 1.2 include:

• SOAP 1.2 utilizes XML Schema as a base structure for the SOAP message. Outside structures may be referenced using XML Base and Xlink conventions (relative URI's).
• Message exchange patterns are no longer described inside of the specification. MEP's are now viewed merely as 'distributed state machines'. This enables the SOAP to get out of the business of describing interactions and instead to put forward a common model that is extensible.
• SOAP 1.2 puts more emphasis on 'Features'. These features are generic methods for extending SOAP according to predefined rules.
• Several incremental changes were made in the HTTP binding.

In addition, a number of 'clean-up' items were added - mostly these clarify ambiguities. SOAP 1.2 is still growing acceptance and will likely not become commonly accepted until it becomes part of a WS-I profile.