Remove est delivery date from shipment status email and tracking page widget

show_est_delivery_date.php

/*
* Remove est delivery date from shipment status email and tracking page widget
*/
add_filter( 'show_est_delivery_date', 'est_delivery_date_in_email', 10, 2 );
function est_delivery_date_in_email( $bool, $provider ) {
	if ( 'USPS' == $provider ) {
		$bool = false;
	}
	return $bool;	
}