Maybe a critical bug

I installed the latest version 1.3.14, although it does not work as I expected.
Even if a form with a checkbox checked is submitted, the subscriber is not on the list.

So, I have taken a look at sources. I seems to find a bug in the source; class-mailpoet-cf7-submit-form.php:

					try {
						$subscriber = \MailPoet\API\API::MP( 'v1' )->addSubscriber( $subscribe_data,
							array_unique( $list_ids ), $options );
					} catch ( Exception $exception ) {
						//If subscriber is already subscribed once and unsubscribed later, then again subscribed to any list, change the status to subscribed and add to the list
						//if ( 'This subscriber already exists.' == $exception->getMessage() ) {
						if ( $exception->getCode() == \MailPoet\API\MP\v1\APIException::SUBSCRIBER_EXISTS ) {
							//Change subscriber status to subscribed
							$subscribe_data['status'] = 'subscribed';

The site that I maintain speaks Japanese. Thus, the message ‘This subscriber already exists.’ in the source would be returned in Japanese. Therefore, even if the subscriber already exists, the == equation would result in failure.

The workaround I took is to use getCode() not getMessage() as shown the above.
In my site, this way works fine at the present time.

I hope this would be helpful to enhance the quality of your plugin.

Many thanks in advance.