Dialog::read

static function read($dialogId, $messageId = null, $userId = null)
{
	$userId = BitrixImCommon::getUserId($userId);
	if (!$userId)
	{
		return false;
	}

	if (BitrixImCommon::isChatId($dialogId))
	{
		$chatId = self::getChatId($dialogId);

		$chat = new CIMChat($userId);
		$result = $chat->SetReadMessage($chatId, $messageId);
	}
	else if ($dialogId === 'notify')
	{
		$notify = new CIMNotify();
		$notify->MarkNotifyRead(0, true);

		return true;
	}
	else
	{
		$CIMMessage = new CIMMessage($userId);
		$result = $CIMMessage->SetReadMessage($dialogId, $messageId);
	}

	return $result;
}