Custom post type broken after WordPress 3.8 upgrade

Hi, I am using event listing post type arranged by dates and it has stopped working after the upgrade. Here is the code which is in functions.php:

add_filter( 'pre_get_posts', 'filter_upcoming' );
    function filter_upcoming( $query ) {
    if (  !is_admin() && is_category('events') && $query->is_main_query() ) {
		$currentdate = date("Y-m-d",mktime(0,0,0,date("m"),date("d")-3,date("Y")));
        $meta_query = array(
                 array(
                    'key'  => 'eventdate' ,
                    'value'  => $currentdate,
                    'compare'  => '>'
                 ),
        );
        $query->set( 'meta_key', 'eventdate' );
        $query->set( 'orderby', 'meta_value' );
        $query->set( 'order', 'ASC' );
        $query->set( 'meta_query', $meta_query );
    }
    return $query;
    }

From what I have read on other post, the problem was something to do with is_category(‘events’).

Hope there is a solution for this.