Using WordPress ‘core_update_footer()’ PHP function

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The core_update_footer() WordPress PHP function returns a message in the admin footer regarding the core update status of the WordPress installation.

Usage

Below is an example of using the core_update_footer() function:

add_filter('update_footer', 'custom_update_footer', 9999);

function custom_update_footer($msg = '') {
  // Code implementation here
}

In this example, the ‘update_footer’ action hook is being used to modify the default WordPress admin footer message. The custom_update_footer function, which is tied to the action hook, receives an optional parameter $msg, a string containing the current admin footer message.

Parameters

  • $msg (string) – This is an optional parameter that represents the current admin footer message.

More information

See WordPress Developer Resources: core_update_footer
This function has been available since WordPress version 2.3.

Examples

add_filter('update_footer', 'custom_update_footer', 9999);

function custom_update_footer($msg = '') {
  return 'Custom footer message';
}

This example simply changes the default admin footer message to ‘Custom footer message’.

Displaying the current WordPress version

add_filter('update_footer', 'version_footer', 9999);

function version_footer($msg = '') {
  return 'Version ' . get_bloginfo('version', 'display');
}

This example changes the admin footer message to display the current version of WordPress.

Displaying a different message for non-admin users

add_filter('update_footer', 'user_specific_footer', 9999);

function user_specific_footer($msg = '') {
  if (!current_user_can('update_core')) {
    return 'You are not allowed to update WordPress.';
  } else {
    return 'Version ' . get_bloginfo('version', 'display');
  }
}

This example changes the footer message based on the user’s capabilities. Non-admin users see a different message.

Displaying update status

add_filter('update_footer', 'update_status_footer', 9999);

function update_status_footer($msg = '') {
  $update_data = get_preferred_from_update_core();

  if ($update_data->response == 'upgrade') {
    return 'New WordPress version available!';
  } else {
    return 'Your WordPress is up to date.';
  }
}

This example checks if there is a new WordPress version available and changes the footer message accordingly.

Providing a link to updates page

add_filter('update_footer', 'update_link_footer', 9999);

function update_link_footer($msg = '') {
  $update_data = get_preferred_from_update_core();

  if ($update_data->response == 'upgrade') {
    return '<a href="' . network_admin_url('update-core.php') . '">Update to new WordPress version now!</a>';
  } else {
    return 'Your WordPress is up to date.';
  }
}

In this example, if a new WordPress version is available, a link to the updates page is displayed in the footer.