const validationSchema = Yup.object({
        contractOptionToExtend: Yup.number('Option to Extend').required().min(0),
        originalEndDate: Yup.date().required().min(Yup.ref('startDate')),
        startDate: contract.leadContract && contract.leadContract.startDate ? Yup.date().min(contract.leadContract.startDate) : Yup.date(),
        ultimateEndDate: Yup.date().min(Yup.ref('currentEndDate')),
        currentEndDate: Yup.date().min(Yup.ref('originalEndDate'))
    });

 const initialValues = {
        contractOptionToExtend: contract && contract.contractOptionToExtendId || -1,
        originalEndDate: contract && contract.originalEndDate,
        startDate: contract && contract.startDate,
        ultimateEndDate: contract && contract.ultimateEndDate,
        currentEndDate: contract && contract.currentEndDate
    };

<DatePicker
                              margin="normal"
                              format="d MMM yyyy"
                                    label="Original End Date"
                                    value={values.originalEndDate}
                                    onChange={handleOriginalEndDateChange}
                                    onBlurCapture={change.bind(null, 'originalEndDate')}
                                    required
                                    id="originalEndDate"
                                    name="originalEndDate"
                                    autoOk={true}
                                    error={touched.originalEndDate && Boolean(errors.originalEndDate)}
                                    helperText={touched.originalEndDate ? errors.originalEndDate : ''}
                                />