72 Pa. Stat. § 5971x
Whenever any county, city, borough, town, township, school, or poor taxes, for the tax year one thousand nine hundred and thirty-four or any previous year, have been heretofore returned to the county commissioners, and the lien of such taxes still unpaid has been lost, or the right of the county treasurer to sell the real estate upon which such taxes were liens at the time of such return, has expired by reason of the failure or neglect of the county treasurer to revive such liens by filing the same in the office of the prothonotary, or to adjourn or readjourn any tax sale, or to advertise or give notice of any sale, or of any adjournment, or of any readjournment of sale, as required by law, or to secure the consent of the county commissioners or the approval of the court to any adjournment or readjournment of a tax sale, or to hold a tax sale at or before the time of holding any tax sale on any other year's taxes, the lien of any such taxes is hereby revived, and the right of treasurer's sale thereon is hereby restored, and such liens shall continue for a period of five years from the effective date of this act: Provided, That any such lien be filed in the office of the prothonotary of the proper county within one year after the effective date of this act, and thereafter the revival, preservation, and enforcement of said lien shall be governed in all respects by the provisions of the act of May sixteenth, one thousand nine hundred twenty-three (Pamphlet Laws, two hundred seven).
72 P.S. § 5971x