URL = FunctionParameters["Bitrix24_URL"];

    FieldID = FunctionParameters["Bitrix24_HookTaskFieldID"];
    Title   = "New title";

    Result = OPI_Bitrix24.UpdateCustomTaskField(URL, FieldID, , Title);

    URL   = FunctionParameters["Bitrix24_Domain"];
    Token = FunctionParameters["Bitrix24_Token"];

    FieldID    = FunctionParameters["Bitrix24_TaskFieldID"];
    ExternalID = "NEW_TEXT_FIELD";
    Signature  = New Structure("en,ru", "Updated field", "Izmenennoe pole");

    Result = OPI_Bitrix24.UpdateCustomTaskField(URL, FieldID, ExternalID, , Signature, Token);