Amends the Unified Code of Corrections. Provides that a person serving a sentence under the law in effect prior to February 1, 1978 who is released from imprisonment shall be placed on mandatory supervised release in the same manner and for the same term as provided in the mandatory supervised release provisions of the Code for persons sentenced under determinate sentencing. Provides that any reference to "parole" under the Sentencing Chapter of the Code and the mandatory supervised release provisions of the Code mean "mandatory supervised release". Provides that the changes made by the amendatory Act apply retroactively. Effective immediately.