If you write and contribute plugins to the WordPress Repository then you might be interested in having your plugin be aware of updates you have made available – an admin notice or something similar. Maybe design a clever versioning scheme so that you can inform the user of critical fixes in a more dramatic way than regular patches.

Check For WordPress Plugin Updates

// Your plugin file, perhaps __FILE__?
$plugin_file = 'plugin-name/plugin-file.php';

// Check for Plugin updates, if you want to have the latest (not necessarily recommended)
wp_update_plugins();

// Results of the update check
$update_plugins = get_site_transient( 'update_plugins' );
if ( isset( $update_plugins->response[ $plugin_file ] ) ) {
    // Your plugin needs an update, do something about it?
}

Plugins With Updates

In the result of update_plugins the $update_plugins->response is an array() that will be something like the following, if there is anything else you want to check.

'response' => 
  array (
    'plugin-dir/plugin-file.php' => 
    stdClass::__set_state(array(
       'id' => '12345',
       'slug' => 'plugin-slug',
       'plugin' => 'plugin-name/plugin-file.php',
       'new_version' => '1.2.3',
       'url' => 'https://wordpress.org/plugins/plugin-name/',
       'package' => 'https://downloads.wordpress.org/plugin/plugin-name.1.2.3.zip',
    )),
),

Compare Installed and Available WordPress Plugin Versions

function my_admin_notice() {
    global $my_admin_notice;
    ?>
    <div class="updated">
        <p><?php _e( 'An update is available for your plugin!', 'my-text-domain' ); ?>
        <?php echo $my_admin_notice; ?></p>
    </div>
    <?php
}

function check_update_notices(){
    global $my_admin_notice;
    $plugin_file = 'plugin-name/plugin-file.php';
    $installed_ver = split( ',', $update_plugins->checked[$plugin_file] );
    $available_ver = split( ',', $update_plugins->response[$plugin_file]->new_version );
    $v1 = $installed_ver[0];
    $v2 = $available_ver[0];
    if ( $v1 != $v2 ){
        $behind = $v2-$v1;
        $my_admin_notice = $behind!=1? "Oh no, you're {$behind} major version(s) behind!" : "";
        add_action( 'admin_notices', 'my_admin_notice' );
        return;
    }
}

The post Check For WordPress Plugin Updates appeared first on Justin Silver.