(1) All cities which have been incorporated under or which have accepted the provisions of the act of May 23, 1874 (P.L. 230, No. 152),¹ entitled “An act dividing cities of this State into three classes; regulating the passage of ordinances; providing for contracts for supplies and work for said cities; authorizing the increase of indebtedness, and the creation of a sinking fund to redeem the same; defining and punishing certain offenses in all of said cities; and providing for the incorporation and government of the cities of the third class.”

(2) All cities which have been incorporated under the provisions of the former act of May 23, 1889 (P.L. 277, No. 247),² entitled “An act providing for the incorporation and government of cities of the third class.”

(3) All cities which have been incorporated under the provisions of the former act of June 27, 1913 (P.L. 568, No. 367),³ entitled “An act providing for the incorporation, regulation, and government of cities of the third class; regulating nomination and election of municipal officers therein; and repealing, consolidating, and extending existing laws in relation thereto.”

(4) All cities formed by the consolidation of boroughs having voted separately to become cities in accordance with the provisions of the former act of May 24, 1917 (P.L. 262, No. 143),⁴ entitled “An act to enable two or more boroughs that are contiguous or in close proximity to be united and to become one city, wherever each of said boroughs shall have heretofore voted or shall hereafter vote to become a city of the third class, under laws now enacted or which may hereafter be enacted; and wherever each of said boroughs has duly received or shall hereafter duly receive letters patent constituting it a city of the third class, but where sufficient time shall not have elapsed after the granting of such letters patent for the holding of a municipal election; providing for the consequences of such consolidation, the government of such consolidated city, the payment of the indebtedness of each of the united territories and the enforcement of debts and claims due to and from each, and fixing the jurisdiction over the said consolidated city in the courts of the county in which the majority of its inhabitants shall reside.”

(5) All cities incorporated under the provisions of the former act of June 23, 1931 (P.L. 932, No. 317),⁵ known as The Third Class City Code.

(6) All cities incorporated under the provisions of this part.

(1) To continue operating under the form of government previously selected and exercising powers previously acquired by the city in accordance with the act of July 15, 1957 (P.L. 901, No. 399),⁶ known as the Optional Third Class City Charter Law.

(2) To adopt or continue utilizing a form of government and to acquire or continue exercising powers pursuant to an optional plan or a home rule charter which has been or may be adopted in accordance with the Home Rule Charter and Optional Plans Law.⁷