• use a http proxy server for updates
• enforce ssh
• enable auto-upgrade for WP core, plugins and themes

/** WordPress update via proxy */
define('WP_PROXY_HOST', 'proxy.f1-online.net');
define('WP_PROXY_PORT', '8080');
define('WP_PROXY_BYPASS_HOSTS','localhost');

/** SSH upgrade */
define('FTP_PUBKEY','/home/webmaster/.ssh/id_rsa.pub');
define('FTP_PRIKEY','/home/webmaster/.ssh/id_rsa');
define('FTP_USER','webmaster');
define('FTP_HOST','localhost:22');

/** auto-upgrade WordPress core */
define( 'WP_AUTO_UPDATE_CORE', true );

/** auto-upgrade WordPress plugins*/
add_filter( 'auto_update_plugin', '__return_true' );

/** auto-upgrade WordPress themes */
add_filter( 'auto_update_theme', '__return_true' );

/*** force SSL usage for admin */
define('FORCE_SSL_ADMIN', true);