* Feature (REST): User objects are now returned with all possible attributes everywhere in the API. Previously, only some methods returned the "full" or "extended" representation of User objects. Announcement Thread.

* Changed (REST): The since parameter and If-Modified-Since header are no longer supported.

* Fixed (REST): Methods documented as requiring GET were allowing POST and not counting the rate limit correctly. These methods now require GET and return an error message if POST is used.

* Fixed (REST): The /users/show.$fmt method now thorws a 404 error if no recognized parameters are given.

* Fixed (REST): The deprecated email parameter was being silently ignored, an error is now returned.

* Fixed (OAuth): Rate limiting was incorrectly by IP only when using the Authenitcation header. This has been corrected.

* Fixed (OAuth): Error messaging for OAuth clients is now more detailed.

* Fixed (REST): Direct message objects were not returning the large user representations in json responses. They will now begin doing so.

* Fixed (REST): Calls to direct message XML methods were incorrectly displaying the nilclass root tag. This has been corrected.

* Feature (REST): Added /direct_messages/show/$id.$fmt method (where $id is the direct message id and $fmt is xml or json)

* Feature (OAuth): Added provisional support for "Sign in via Twitter" for OAuth applications. An official annoucement will follow after full support is available.

* Fixed (OAuth): Accented characters in statuses were causing signature error for OAuth clients. This has been corrected.

* Fixed (REST): Attempting to direct message yourself failed and returned a direct message from cache. You can now direct message yourself again.

* Fixed (OAuth): non-ASCII characters in POST parameters were incompatible afte the April 9th change. That incompatibility was corrected.

* Fixed (REST): The since_id parameter now works on the /direct_messages/sent method

* Fixed (OAuth): All application image updates were reporting the image was too large. This has been corrected.

* Fixed (REST): Changing your profile image on the web was not reflected in the API. This has been corrected.

* Fixed (Search): The atom results did not contain a language element for each status. A twitter:lang element has been added.

* Fixed (REST): When sending Direct Messages reaching the limit now returns HTTP 403 instead of HTTP 500.

* Fixed (REST): When uploading a new background image via the API the result was not immediately reflected. This has now been fixed.

* Feature (REST): Support the user_id and screen_name parameters for friendships/create, friendships/destroy, notifications/create, and notifications/leave.

* Feature (REST): Support the max_id parameter for direct message pagination.

* Fixed (REST): Basic authentication now works with passwords containing a colon. (issue 496)

* Fixed (REST): Error message during downtime now matches documented response. (issue 300)

* Deprecated (REST): Support for the oauth_callback parameter has been removed due to security vulnerability. (discussion)

* Fixed (OAuth): OAuth images are properly served from through HTTPS. (issue 476)

* Feature (REST): The in_reply_to_status_id can now reference any mentioned user. (announcement)

* Feature (REST): The social graph methods now support pagination via the page parameter so you can work with very large users. (issue 518)