petitioner start date h1b on visa appointment

I am currently in US and my extension approved and it is valid from 02/04/2016 and my current petition expires on 02/03/2016
Petitioner's Name: Employer name
Start Date: ? is it my old petition validity start date or new petition validity start date(02/04/2016) or my return date to US?
Receipt Number: new petition number
Expiration Date: new petition expiry date

Petitioner's Name: *
Start Date: *
Date Format MM/DD/YYYY
Receipt Number: *
Expiration Date:*
Date Format MM/DD/YYYY

Please suggest what is the start date i need to enter?