In addition to the method of procuring the continuance of the lien provided in section 12-174, the tax collector of any municipality may continue any tax lien upon any item of real estate by making out a certificate containing the information required by the provisions of section 12-173. Each certificate authorized by the provisions of this section shall be filed in the office of the town clerk of the town in which such real estate is situated not later than two years after the first installment of the tax, or the whole tax in case installment payments are not authorized, has become due, and the town clerk shall record such certificate in the land records of such town, provided the tax collector shall notify the owner of such real estate of the intent to file a lien by mail not later than fifteen days prior to the filing of such lien. Failure to notify such owner shall not affect the validity of the lien. Each such tax, as it may have been increased by interest, fees and charges provided for by law, shall remain a lien upon such real estate from the date of the filing of such certificate; and any tax lien so continued, when the amount due has been paid, may be discharged by a certificate of the then tax collector recorded in such land records; but any tax lien upon private property which has been recorded in the land records of any town for more than fifteen years from the due date of the tax shall be invalid, and such property shall be free from the encumbrance of such lien, unless an action of foreclosure has been commenced during such period of fifteen years and a notice of lis pendens filed for record, and the tax collector shall, if no such notice has been filed, upon the request of any interested person, discharge such lien of record by filing a discharge of lien in the office of the town clerk, and the town clerk shall record a discharge of lien in the land records.