zentao/extension/ipd/workflowlinkage/config.php

<?php
$config->workflowlinkage->operatorList['=='] = '=';
$config->workflowlinkage->operatorList['!='] = '!=';
$config->workflowlinkage->operatorList['>']  = '>';
$config->workflowlinkage->operatorList['>='] = '>=';
$config->workflowlinkage->operatorList['<']  = '<';
$config->workflowlinkage->operatorList['<='] = '<=';