Related Rule
Practice Relating to Rule 101. The Principle of Legality
Serbia’s Criminal Code (2005) states:
No one may be punished, or other criminal sanction imposed, for an offence that did not constitute a criminal offence at the time it was committed, nor may punishment or other criminal sanction be imposed that was not applicable at the time the criminal offence was committed. 
Serbia, Criminal Code, 2005, Article 1.