As per the recent posting on Outlook Live Answers, there are some changes that will need to be made if you are using SSO.
The URL used to validate a Windows Live ID is changing, so any single sign-on solutions that are built using the Microsoft Live@edu SSO Toolkit must be modified to change the URL value, or users will not be able to log in through single-sign on. Depending on your implementation, this is a simple change to one line in a configuration file or in the code, and does not require new certificates. The new URL is available beginning now, so changes can be made anytime up to October 1st.
What is changing?
The only change is to the URL used to validate a Windows Live ID.
The new URL can be used starting now, and must be changed by October 1.
Important: The old Windows Live ID URL will be retired on October 1, so changes must be implemented by then or users will no longer be able to log in.
A new version of the Live@edu SSO Toolkit with updated sample code for the GetSLT method and updated documentation will be available to download from Microsoft Connect on August 25, 2011.
If you have a single sign-on solution built with the Live@edu SSO Toolkit, check with your Microsoft Partner to make sure they have updated your solution.
If you developed your own solution, update the Windows Live ID server URL. In the SSO Toolkit sample code, this URL is set in the CredentialWebServiceUrl parameter in the GetSLT method.