GENERAL PART
Chapter I
THE CRIMINAL CODE AND THE PRINCIPLES OF ITS APPLICATION
Article 10. Retroactive Effect of Criminal Law
(1) Criminal law that eliminates the criminal nature of an act, that makes the punishment milder, or that in any other way improves the situation of the person who committed the crime shall have retroactive effect, meaning that it shall extend to persons who committed the respective acts prior to the date when this law took effect, including persons who are serving sentences or who served sentences but have criminal backgrounds.
(2) Criminal law that increases the punishment or worsens the situation of a person guilty of the commission of a crime shall not have retroactive effect.
EDIT.