73 Pa. Stat. § 820.704
No person or qualified business in a subzone, improvement subzone or expansion subzone shall be required to pay any fee authorized pursuant to a mercantile license tax imposed under the act of June 20, 1947 (P.L. 745, No. 320), entitled, as amended, "An act to provide revenue for school districts of the first class A by imposing a temporary mercantile license tax on persons engaging in certain occupations and businesses therein; providing for its levy and collection; for the issuance of mercantile licenses upon the payment of fees therefor; conferring and imposing powers and duties on boards of public education, receivers of school taxes and school treasurers in such districts; saving certain ordinances of council of certain cities, and providing compensation for certain officers, and employes and imposing penalties."
73 P.S. § 820.704