Version 1.1 of the Auth API differs from Version 1.0 in several important ways:
API CHANGES:
ReSTful calls no longer use HTTP headers for request or response parameters. Parameters are now sent via the XML or JSON message body.
HTTP responses are in XML or JSON format, depending upon the request's
Acceptheader or the requested resource's extension (.xmlor.json).
NEW FEATURES:
Service endpoint URLs are now capable of specifying a region.
