Periods for submission of annual income tax returns and the payment period of the first installment are extended until 30th April 2020 through the Tax Procedure Law Circular No.125 ("Circular"), published on the website of the Revenue Administration on 17th March 2020.
You may find the full text of the Circular here.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.