Plupload 2.x in WordPress 3.9

Plupload is the library that powers most of the file upload interfaces in WordPress, and in 3.9 we’ve updated the bundled library to version 2.1.1 (#25663). Here are some of things that have changed, which may affect WordPress plugins and themes.

If you’re using direct references to Plupload’s runtime .js files, such as plupload.html5.js, note that these files are now gone. The following script handles were removed: plupload-html5, plupload-flash, plupload-silverlight and plupload-html4. If you need to enqueue the Plupload library, just use the plupload handle.

If you’re constructing your own Plupload settings array vs. using wp_plupload_default_settings() and/or the _wpPluploadSettings object, note that some of the arguments have changed, most notably:

  • flash_swf_url should point to the new Moxie.swf file (See update)
  • Similarly, silverlight_xap_url should use the new Moxie.xap (See update)
  • The multiple_queues argument is no longer used
  • The max_file_size key has been moved to the filters array
  • The filters array now supports multiple keys, and the list of file types array has been moved to its mime_types key

To illustrate that with code:

$settings = array(
    // ...
    'flash_swf_url' => includes_url( 'js/plupload/plupload.flash.swf' ), // Unchanged
    'silverlight_xap_url' => includes_url( 'js/plupload/plupload.silverlight.xap' ), // Unchanged
    'filters' => array( 
        'max_file_size' => $max_upload_size . 'b', 

Plupload version 2.1.1 has also added some exciting new options and methods, which you can find in the updated documentation.

As a result of this update in WordPress 3.9 we were able to add drag and drop upload support directly to our TinyMCE editor (#19845), and we’ve also added a new boolean flag to wp_editor(), which you can use to enable drag and drop upload support in your own instance of the editor (#27465):

wp_editor( '', 'my-editor', array(
    // ...
    'drag_drop_upload' => true,
) );

If you run into any problems with this update in 3.9, please leave a comment on this post and we’ll be happy to help you out!

Update: I opened #27763 to address some of the compatibility issues around the update. We might be renaming the swf/xap files for backwards compatibility.

Update, April 13: The original swf/xap filenames were restored.