General Part
Chapter I
General Provisions
Section 5. Time When The Criminal Law is In Force
(1) The criminality and punishability of an offence (act or failure to act) are determined by the law, which was in force at the time the offence was committed.
(2) A law which recognises an offence as not punishable, reduces the punishment or otherwise is beneficial to a person, as long as it is not provided otherwise by the applicable law, has retrospective effect, that is, it applies to offences which have been committed prior to the applicable law coming into force, as well as to a person who is serving a punishment or has served a punishment but regarding whom conviction remains in effect.
(3) A law, which recognises an offence as punishable, increases the punishment, or is otherwise not beneficial to a person, does not have retrospective effect.
EDIT.