filling of itr for the A. Y. 2017-18

Yes, after getting permission from JCIT/ ITO of your Jurisdiction u/s 119(2)(b) IT act, for delay in filing return. (if ITR not filed originally)

But if return filed earlier, you can revise it.

guides/section-119-2b

circular/circular9_2015

section-119-income-tax-act

letter-format-for-requestion-condo-nation-of-delay

https://tax guru.in/income-tax/missed-to-file-the-return-of-income-of-earlier-years-and-claim-refunds-or-benefit-of-carry-forward-loss.H T M L