(5) Whenever a lessor who receives a security deposit transfers his interest in the dwelling unit for which the security deposit is held, whether by sale, assignment, death, appointment of a receiver or trustee in bankruptcy, or otherwise, the lessor shall transfer such security deposit together with any interest which has accrued thereon for the benefit of the tenant who made such security deposit to his successor in interest, and said successor in interest shall be liable for the retention and return of said security deposit in accordance with the provisions of this section from the date upon which said transfer is made; provided however, that the granting of a mortgage on such premises shall not be a transfer of interest. The successor in interest shall, within forty-five days from the date of said transfer, notify the tenant who made such security deposit that such security deposit was transferred to him and that he is holding said security deposit. Such notice shall also contain the lessor's name, business address, and business telephone number, and the name, business address, and business telephone number of his agent, if any. Said notice shall be in writing.