Message::isViewedByOthers

public function isViewedByOthers(): bool
{
	if (isset($this->isViewedByOthers))
	{
		return $this->isViewedByOthers;
	}

	$this->isViewedByOthers = (new ViewedService())->getMessageStatus($this->getMessageId()) === IM_MESSAGE_STATUS_DELIVERED;

	return $this->isViewedByOthers;
}