Fixed (OAuth): Internet Explorer users were not being correctly redirected back to the originating site when using the authenticate method. (issue 644)

Fixed (OAuth): Internet Explorer users were seeing a warning about insecure items on OAuth pages.

Fixed (REST): The source parameter was incorrectly being reported as 'from web' in all cases (issue 634)

Feature (REST): Added access to saved search data: saved_searches, saved_searches/show, saved_searches/create, and saved_searches/destroy. (issue 605)

Feature (OAuth): Updated OAuth to 1.0a and added a PIN-based desktop workflow for OAuth apps. (announcement)

Fixed (Search): Search errors are now returned in the API format requested (issue 509)

Fixed (Search): Searches for never-used phrases incorrectly returned an error rather than 0 results. (issue 740)

Fixed (Search): The combinations of some operators with since_id incorrectly returned an error, now it returns results. (issue 742)

Feature (REST): Added screen_name and user_id attributes to direct_messages/new for disambiguation (issue 550, documentation)

Feature (REST): Added new friendships/show method (issue 474, documentation)

Fixed (REST): Partially fixed issue with tiling background images via the API (issue 650)

Fixed (OAuth): Added a more helpful error message when you try to use a request token in place of an access token.

Fixed (OAuth): Improved error handling when invalid data is submitted in place of a token.

Fixed (REST): The JSON returned in maintenance mode now correctly contains null rather than NULL (issue 703)

Fixed (Mail): Improved outbound email reliability (for apps parsing DM/friend emails)

Fixed (Search): Searches for accented and non-accented words are now combined. (issue 503)

Fixed (REST): The new friendships/show method no longer returns 502 on large users. (issue 757)

Feature (Search): Added Farsi/Persian to the list of available languages.