53 Pa. Stat. § 7435
Whenever, heretofore, any tax lien has been entered in the office of the prothonotary of any county having a controller, and the claim for such tax whereupon the lien was filed was not signed by, and did not have stamped thereon a facsimile signature of the controller of such county as required by section ten of the act, approved the sixteenth day of May, one thousand nine hundred twenty-three (Pamphlet Laws, two hundred seven), entitled "An act providing when, how, upon what property, and to what extent, liens shall be allowed for taxes and for municipal improvements, for the removal of nuisances, and for water rents or rates, sewer rates, and lighting rates; for the procedure upon claims filed therefor; the methods for preserving such liens and enforcing payment of such claims; the effect of judicial sales of the properties liened; the distribution of the proceeds of such sales, and the redemption of the property therefrom; for the lien and collection of certain taxes heretofore assessed, and of claims for municipal improvements made and nuisances removed, within six months before the passage of this act; and for the procedure on tax and municipal claims filed under other and prior acts of Assembly," as amended by the act, approved the second day of July, one thousand nine hundred thirty-seven (Pamphlet Laws, two thousand eight hundred eight), such lien shall not be invalidated, discharged or set aside by reason of such defect if, in all other respects, such claim was filed and lien entered thereon as provided by law; and all such tax liens are hereby ratified, confirmed and validated.
53 P.S. § 7435