https://codex.wordpress.org/Version_3.5

</p>

Highlights

</p>

  • New Media Manager
    • Beautiful interface: A streamlined, all-new experience
    • Create galleries faster with drag-and-drop reordering, inline caption editing, and simplified controls
    • Insert multiple images at once with Shift/Ctrl+click



</p>

  • New Default Theme - Twenty Twelve
    • Simple, flexible, elegant
    • Mobile-first, responsive design
    • Gorgeous Open Sans typeface
    • Uses the latest Theme Features



</p>

  • Admin Enhancements
    • New Welcome Screen
    • Retina-Ready (HiDPI) Admin
    • Hide Link Manager for new installs
    • Better accessibility for screenreaders, touch devices, and keyboard users
    • More polish on admin screens, including a new color picker



</p>

  • For Developers
      • WP_Comment_Query and WP_User_Query accept now meta queries just like WP_Query
      • Meta queries now support querying for objects without a particular meta key
      • Post objects are now instances of a WP_Post class, which improves performance and caching
      • Multisite's switch_to_blog() is now significantly faster and more reliable
      • WordPress has added the Underscore and Backbone JavaScript libraries
      • TinyMCE, jQuery, jQuery UI, and SimplePie have all been updated to the latest versions
      • Image Editing API for cropping, scaling, etc., that uses ImageMagick as well as GD
      • XML-RPC: Now always enabled and supports fetching users, managing post revisions, searching




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