53 Pa. Stat. § 56709.2
Notwithstanding section 533(b) of the act of December 13, 1988 (P.L. 1121, No. 145), known as the "Local Tax Reform Act," a township of the first class or a home rule municipality that previously had been a township of the first class, and that has a population exceeding 70,000 which, before December 1, 1988, has levied, assessed or collected or provided for the levying, assessment or collection of a mercantile tax on gross receipts or parts of gross receipts may levy, assess and collect or provide for the levying, assessment or collection of mercantile and business privilege taxes on gross receipts or parts of gross receipts. This authority shall apply to the tax year beginning January 1, 1998, and to each tax year thereafter.
53 P.S. § 56709.2