Option to opt for the new tax regime will be available for the taxpayers filing return of ITR 1 or ITR 2 in the return itself.
There is no need for separate filing of Form 10-IE Read below picture – relevant portion extracted – 
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The author, CA Jayprakash Pandey is a practicing Chartered Accountant (Founder of Jayprakash P & Company) having Office at Mumbai, with more than 5 years of professional cum practical experience, Direct Tax, International Taxation, Indirect Tax & FEMA related advisory, litigation & compliance matters.