Disable All Automatic Updates

<?php
// Disable automatic background updates for all components.
add_filter( 'automatic_updater_disabled',  '__return_true'  );
add_filter( 'auto_update_core',            '__return_false' );
add_filter( 'auto_update_plugin',          '__return_false' );
add_filter( 'auto_update_theme',           '__return_false' );
add_filter( 'auto_update_translation',     '__return_false' );
add_filter( 'wp_auto_update_core',         '__return_false' );

// Also disable the auto-update UI toggle in Plugins/Themes screens
// so it accurately reflects the site's configuration.
add_filter( 'plugins_auto_update_enabled', '__return_false' );
add_filter( 'themes_auto_update_enabled',  '__return_false' );