To modify the voucher series in Voucher through bulk updation, follow these steps:
Step 1: Take the latest backup of your data.
Step 2: Go to administration section then click on bulk updation.
Step 3: Choose bulk voucher creation and modification then select the required voucher type.
Step 4: Click on configure then create format then select field which you have entered in voucher then save it.
Step 5: Click on modify voucher, select format then click on update tab.
Step 6: Specify the voucher series, starting and ending date, click on load vouchers then save the details after modification.