Redirect All Emails on Staging Site

redirect-emails.php

add_filter( 'wp_mail', 'ox_redirect_email_filter', 10, 1 );

function ox_redirect_email_filter( $args ) {

	// Get original To address
	$original_to = $args['to'];

	// Send to developer only
	$args['to'] = 'oterox@developer.com';

	// Show original To address in message for debug
	$args['message'] = sprintf( "Message is originally sent to: [%s]", $original_to ) . $args['message'];

	return $args;
}