72 Pa. Stat. § 5573
All penalties and interest imposed on unpaid delinquent county (except counties of the second class), city (except cities of the first and second class), borough, town, township, school district (except school districts of the first class), poor district (except in counties of the second class), and county institution district (except counties of the second class) taxes for the tax year one thousand nine hundred and forty and all previous years, assessed and levied against any parcel or parcels of real estate, are hereby abated without the necessity of further action by the authority levying the tax, if the unpaid delinquent taxes are paid as hereinafter provided, unless the authority levying the tax shall have notified the county treasurer within thirty days after this act becomes effective that the taxing authority has rejected by a majority vote the provisions of this act.
In order to receive the benefits of the installment system of payment provided by this act, twenty per centum or more of the unpaid delinquent taxes due for the year one thousand nine hundred and forty and for all previous years shall be paid on or before the first day of November, one thousand nine hundred and forty-one, twenty per centum or more on or before the first day of November, one thousand nine hundred and forty-two, twenty per centum or more on or before the first day of November, one thousand nine hundred and forty-three, twenty per centum or more on or before the first day of November, one thousand nine hundred and forty-four, and the unpaid balance on or before the first day of November, one thousand nine hundred and forty-five: Provided, That the taxes on such parcel or parcels of real estate levied for the year one thousand nine hundred and forty-one, together with any interest and penalties due thereon, shall be paid on or before the first day of November, one thousand nine hundred and forty-one: And, provided further, That the respective current taxes on such parcel or parcels of real estate levied for the years subsequent to the year one thousand nine hundred and forty-one during such installment periods, assessed and levied by such taxing authority, shall be paid before they become delinquent. For the purposes of this act a tax shall be deemed to become delinquent on the date when a penalty attaches to the tax. If, and whenever, any of the said current taxes, or any of the said installments, are not paid when due and payable as herein provided, then, and in that event, the total amount of the abated penalties and interest shall be revived and added to the unpaid taxes with the same force and effect as if such abated penalties and interest, or portion thereof, had never been abated, and the taxpayer shall not thereafter be entitled to any further benefits or privileges under this act.
72 P.S. § 5573