First we have to release the RFP for MMRCA 2.0. And then we need to allow the IAF some time with the current crop of Rafales we ordered, so that any new upgrades or changes that we need can become part of a new deal.
Furthermore, we need to give some time to Dassault so that Rafale F4.1 can become available. This way we can bring in the F4.1 instead of F3R. F4.1 can become available after 2022. While the French have already ordered 28 F4.1s, we still have to wait and see if it's a good prospect.
I'm assuming Modi may ask for a second batch by mid-2020, or possibly mid-2021. And sign it by mid-2022. I hope it's all done by end-2021 though.