On 29 October 2025, the President of the Slovak Republic, Peter Pellegrini, signed the law ratifying the pending protocol to the 2016 income tax treaty with Iran. The protocol, signed 9 April 2025, is the first to amend the treaty. It will enter into force on the first day of the third month after the ratification instruments are exchanged and will apply from 1 January of the year following its entry into force.