Every three years, and for the first time by 29 November 2019, the Commission shall submit a report to the European Parliament and to the Council on the application of this Directive in the Member States and shall propose any amendments necessary. The report shall focus in particular on the assessment of the proper functioning of the intra-EU mobility scheme and on possible misuses of such a scheme as well as its interaction with the Schengen acquis. The Commission shall in particular assess the practical application of Articles 20, 21, 22, 23 and 26.