ajoah on "[Plugin: WP Mail SMTP] OpenSSL changes in PHP 5.6.x"

There is a filter, you do not need to edit plugin file.

add_filter('wp_mail_smtp_custom_options','my_wp_mail_smtp_custom_options');

function my_wp_mail_smtp_custom_options($phpmailer){

	$phpmailer->SMTPOptions = [
		'ssl' => [
			'verify_peer' => false
		]
	];

	return $phpmailer;
}