How can I disable the update notice for non-administrators?

You may have to adjust the capability.

add_action( 'admin_init', 'hide_update_msg', 1 );
function hide_update_msg()
{
    ! current_user_can( 'install_plugins' ) 
        and remove_action( 'admin_notices', 'update_nag', 3 );
}

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)