Colorado constitution
Article XII
Section 13

(11) Persons certified to classes and positions under the classified civil service of the state immediately prior to July 1, 1971, persons having served for six months or more as provisional or acting provisional employees in such positions immediately prior to such date, and all persons having served six months or more in positions not within the classified civil service immediately prior to such date but included in the personnel system by this section, shall be certified to comparable positions, and grades and classifications, under the personnel system, and shall not be subject to probationary periods of employment. All other persons in positions under the personnel system shall be subject to the provisions of this section concerning initial appointment on or after such date.