WordPress snippet to completely disable and remove all admin notices, dashboard notifications, update nags, and plugin notices. Works with all WordPress versions, prevents third-party plugins from showing notices, and follows WordPress coding standards. Can be used in themes, plugins, or with Code Snippets plugin.

wordpress-disable-all-admin-notices.php

<?php
/**
 * Disable Admin Notices WordPress
 * Description: Completely removes all admin notices from the WordPress dashboard,
 * including core WordPress notices and those added by plugins and themes.
 * @author Faisal Ahammad <[email protected]>
 */

// Exit if accessed directly
if (!defined('ABSPATH')) {
    exit;
}

/**
 * Main class to handle admin notice removal
 */
class Admin_Notice_Remover {

    /**
     * Initialize the notice remover
     *
     * @return void
     */
    public function init() {
        // Remove all admin notices
        add_action('admin_init', [$this, 'remove_all_notices'], 1);
        
        // Remove specific notice hooks
        add_action('admin_head', [$this, 'remove_notice_output'], 1);
        
        // Disable notice output
        add_action('admin_notices', [$this, 'disable_notices'], 1);
        add_action('all_admin_notices', [$this, 'disable_notices'], 1);
        add_action('user_admin_notices', [$this, 'disable_notices'], 1);
        add_action('network_admin_notices', [$this, 'disable_notices'], 1);
        
        // Remove update nags
        add_action('admin_init', [$this, 'remove_update_nags'], 1);
    }

    /**
     * Remove all notices using remove_all_actions
     *
     * @return void
     */
    public function remove_all_notices() {
        remove_all_actions('admin_notices');
        remove_all_actions('all_admin_notices');
        remove_all_actions('user_admin_notices');
        remove_all_actions('network_admin_notices');
    }

    /**
     * Remove notice output using CSS
     *
     * @return void
     */
    public function remove_notice_output() {
        ?>
        <style>
            .notice, 
            .notice-error, 
            .notice-warning, 
            .notice-success, 
            .notice-info, 
            .updated, 
            .error, 
            .update-nag {
                display: none !important;
            }
        </style>
        <?php
    }

    /**
     * Disable notices by returning false
     *
     * @return bool
     */
    public function disable_notices() {
        return false;
    }

    /**
     * Remove update nags
     *
     * @return void
     */
    public function remove_update_nags() {
        remove_action('admin_notices', 'update_nag', 3);
        remove_action('admin_notices', 'maintenance_nag', 10);
    }
}

// Initialize the notice remover
add_action('plugins_loaded', function() {
    $notice_remover = new Admin_Notice_Remover();
    $notice_remover->init();
});