src/Data/BizField.php
public function getValueOnUpdate()
    {
        if ($this->valueOnUpdate !== null)
            return $this->getSqlValue(Expression::evaluateExpression($this->valueOnUpdate, $this->getDataObj()));
        return "";
    }
public function getValueOnUpdate()
    {
        if ($this->valueOnUpdate !== null)
            return $this->getSqlValue(Expression::evaluateExpression($this->valueOnUpdate, $this->getDataObj()));
        return "";
    }
Get the value when a record is updated

@return mixed the value of the field