use Bitrix\Main\Mail\Event;
use Bitrix\Main\EventManager;
use Bitrix\Main\Diag\Debug;
use Bitrix\Main\Loader;

$onBeforeIBlockUpdateHandler = EventManager::getInstance()->addEventHandler(
    "iblock",
    "OnBeforeIBlockUpdate",
    array(
        "MyClass",
        "OnBeforeIBlockUpdateHandler"
    )
);
$onAfterIBlockUpdateHandler = EventManager::getInstance()->addEventHandler(
    "iblock",
    "OnAfterIBlockUpdate",
    array(
        "MyClass",
        "OnAfterIBlockUpdateHandler"
    )
);

class MyClass{
    function OnBeforeIBlockUpdateHandler(&$arFields){
        $iblockRres = CIBlock::GetByID($arFields["ID"]);
        if($ar_res = $iblockRres->GetNext()){
            $arIblock = $ar_res;
        }

        $_SESSION['EDIT_IBLOCK']['ID'] = $arFields['ID'];
        $_SESSION['EDIT_IBLOCK']['OLD_NAME'] = $arIblock['NAME'];
        $_SESSION['EDIT_IBLOCK']['NEW_NAME'] = $arFields['NAME'];

    }

    function OnAfterIBlockUpdateHandler(&$arFields){
        if((isset($_SESSION['EDIT_IBLOCK'])) && (!empty($_SESSION['EDIT_IBLOCK']))){
            Event::send(array(
                "EVENT_NAME" => "EDIT_IBLOCK",
                "LID" => "s1",
                "C_FIELDS" => $_SESSION['EDIT_IBLOCK'],
                "N",
                84
            ));
        }
        unset($_SESSION['EDIT_IBLOCK']);
    }
}