Here are the defect corrections and enhancements for the 6/8/2012 API release.
WebService Schedule Campaign - Cannot Schedule a Campaign for an SO
An issue arose with a related defect correction that was preventing legitimate users from sending campaigns. This has been corrected so that users and applications can send campaigns correctly through the APIs.
Facebook JMML app v2
We delivered a new version of our Facebook JMML app that uses the latest Facebook technology, uses OAuth 2 to authenticate with Constant Contact, and that improves the configuration and usability of the app.
Welcome Back' message not needed on login page for OAuth authentication
We recently rolled out our new login page (login.constantcontact.com). When entered through an OAuth flow, there is no need for the 'Welcome Back' message, so we disabled that message in this case.
Auth app cannot be iframed.
Previously, it was possible to iframe the auth app (login.constantcontact.com), which is used a part of OAuth authentication flows. This violates basic security considerations, as iframed login pages are easily spoofed. The Auth app starting with this release can no longer be iframed. Developers using OAuth flows inside of iframes should change their app to remove the iframe and have the auth flow run in a separate browser window or tab.