CAllCrmActivity::SaveTask

static function SaveTask(&$arFields)
{
	$typeID = self::GetActivityType($arFields);
	$associatedEntityID = isset($arFields['ASSOCIATED_ENTITY_ID']) ? (int)$arFields['ASSOCIATED_ENTITY_ID'] : 0;

	if ($typeID !== CCrmActivityType::Task || $associatedEntityID <= 0)
		return false;

	//compatible
	$result = \Bitrix\Crm\Activity\Provider\Task::updateAssociatedEntity($associatedEntityID, $arFields);
	return $result->isSuccess();
}