With the Tax Procedure Law Circular No. 130 published on 12 May 2020,
- the deadline to submit advance tax returns for income tax and corporate income tax in relation to the first quarter (January-February-March) of the year 2020, which was due by the end of 18 May 2020, and
- to pay the taxes that have accrued on these returns
has been postponed to the end of Thursday, 28 May 2020.
You can reach to the said Circular from this link.