All sums assessed by the association of unit owners, but unpaid for the share of the common expenses chargeable to any unit shall constitute a lien on such unit prior to all other liens, except only tax liens on the unit in favor of any assessing unit and special district, including any state and federal tax liens, and all sums unpaid on mortgages of record. Such lien may be claimed 60 days after the due date of the assessment. It shall be signed by the manager or one of the members of the board of directors and shall be perfected by filing it in the registry of deeds of the county in which the unit lies, and by leaving a true and attested copy thereof with the unit owner against whom such lien is claimed or at his usual place of abode, or, if such unit owner resides outside the municipality in which the unit lies, by mailing such copy to him at the place where he resides. Such lien shall be limited and discharged in accordance with the general statutes. Such lien may be foreclosed by action by the manager or board of directors, acting on behalf of the unit owners, in like manner as a mortgage of real property including reimbursement for costs and reasonable attorneys' fees. In any such foreclosure the unit owner shall be required to pay a reasonable rental for the unit, if so provided in the bylaws and the plaintiff in such foreclosure shall be entitled to the appointment of a receiver to collect the same. The manager or board of directors, acting on behalf of the unit owners, shall have power, unless prohibited by the declaration, to bid in the unit at foreclosure sale, and to acquire and hold, lease, mortgage and convey the same. Action to recover a money judgment for unpaid common expenses shall be maintainable without foreclosing or waiving the lien securing the same. Where a mortgagee or a purchaser at a foreclosure sale obtains title to a unit, such acquirer of title, his heirs, successors and assigns, shall not be liable for the entire unpaid share of the common expenses or assessments by the association of unit owners chargeable to such unit which became due prior to the acquisition of title to such unit by such acquirer, but such expenses or assessments shall become common expenses collectible from all of the unit owners including such acquirer, his heirs, successors and assigns.   [PL 1965, c. 357 (NEW).]