钩子构建要明确动作钩子的名称：

global $pagenow;
if ( \'plugins.php\' === $pagenow )
{
    // Better update message
    $file   = basename( __FILE__ );
    $folder = basename( dirname( __FILE__ ) );
    $hook = "in_plugin_update_message-{$folder}/{$file}";
    add_action( $hook, \'your_update_message_cb\', 20, 2 );
}

挂钩回调函数

函数本身有两个$variables 附件：$plugins_data &；$r, 可以通过插件访问。

/**
 * Displays an update message for plugin list screens.
 * Shows only the version updates from the current until the newest version
 * 
 * @param (array) $plugin_data
 * @param (object) $r
 * @return (string) $output
 */
function your_update_message_cb( $plugin_data, $r )
{
    // readme contents
    $data       = file_get_contents( \'http://plugins.trac.wordpress.org/browser/YOUR_PLUGIN_FOLDER_NAME_IN_THE_OFFICIAL_REPO/trunk/readme.txt?format=txt\' );

    // assuming you\'ve got a Changelog section
    // @example == Changelog ==
    $changelog  = stristr( $data, \'== Changelog ==\' );

    // assuming you\'ve got a Screenshots section
    // @example == Screenshots ==
    $changelog  = stristr( $changelog, \'== Screenshots ==\', true );

    // only return for the current & later versions
    $curr_ver   = get_plugin_data(\'Version\');

    // assuming you use "= v" to prepend your version numbers
    // @example = v0.2.1 =
    $changelog  = stristr( $changelog, "= v{$curr_ver}" );

    // uncomment the next line to var_export $var contents for dev:
    # echo \'<pre>\'.var_export( $plugin_data, false ).\'<br />\'.var_export( $r, false ).\'</pre>\';

    // echo stuff....
    $output = \'whatever you want to do\';
    return print $output;
}

<小时>

Footnote:

^{可以在Internal link checker 插件}

Addition:

plugin_basename(__FILE__) 可以用来代替上面的两行。此外，检查当前页面是否是插件页面并不是真正必要的，因为该函数无论如何只会由该页面调用。（非常小的）好处仍然是您没有附加另一个回调。由于这个答案已经很老了，虽然这种方法仍然可以正常工作，但现在可以对照get_current_screen().