This file has been discontinued by the exchange (refer to Circular NSE/FAOP/61157)
The alternative to it is the main contract master file that is now available on the website (in Reports page, the report named F&O-MII - Contract File (.gz) - example link). This is a much bigger file as it has all contracts, in it mainly one needs to refer to the fields named MaxTradQty (Column AO, need to subtract 1 from this value)
