The duty of an annuitant, who is receiving a disability annuity, to furnish a written statement concerning his earnings, as provided in section 5908(b) of the code (relating to rights and duties of annuitants), shall continue until the attainment of superannuation age of 50 or 60, as the case may be, depending upon the category of employment at the time of entering upon disability retirement.
4 Pa. Code § 249.8