Greece is introducing a tax reform to increase efficiency, prevent fraud and close its VAT gap by digitising its tax system. Although 1 October 2020 had been the intended date for mandatory participation, late changes announced by the tax authority meant only some taxpayers were obliged to use it during 2020. For others, participation during the first three months has been voluntary. The date was postponed by the Greek government to 1 January 2021, and has since been delayed further and will now not be mandatory for all until 1 July 2021.
Source Sovos