Verification::isMailingsUsed

static function isMailingsUsed(): bool
{
	$letters = \Bitrix\Sender\Internals\Model\LetterTable::getList([
		'select' => ['ID'],
		'filter' => [
			'=STATUS' => \Bitrix\Sender\Dispatch\Semantics::getFinishStates(),
			'=MESSAGE_CODE' => \Bitrix\Sender\Message\iBase::CODE_MAIL
		],
		'limit' => 1,
	]);

	return (bool)$letters->fetch();
}