43 Pa. Stat. § 808
Final payment of compensation claimed under the provisions of this act shall not be made more than two years from the last day of the week for which compensation is claimed if such final payment had not been made within such two-year period because the claimant (1) is reported by the postal authorities as "unknown" at the last address which the employe has given to the department, (2) has failed to properly notify the department that he has not received the compensation claimed, (3) has failed to have presented to the State Treasurer for final payment a check received in payment of the compensation claimed, or (4) has failed to properly request the re-issuance of a check which has become lost or destroyed or the validity date of which has expired: Provided, That one year has elapsed from the date the check was issued or, if no check has been issued, from the last date that the claimant requested payment. The provisions of this section shall also apply to the endorser of any check issued in payment of compensation under the provisions of this act.
43 P.S. § 808