Any notice from LESSOR to LESSEE relating to the leased premises or to the occupancy thereof shall be deemed duly served when left at the leased premises, or served by constable, or sent to the leased premises or to the last address designated by notice in accordance with this section, by certified or registered mail, return receipt requested, postage prepaid, or by recognized courier service with a receipt therefor, addressed to LESSEE. Any notice from LESSEE to LESSOR relating to the leased premises or to the occupancy thereof shall be deemed duly served when served by constable, or delivered to LESSOR by certified or registered mail, return receipt requested, postage prepaid, or by recognized courier service with a receipt therefor, addressed to LESSOR at 200 West Cummings Park, Woburn, MA 01801 or at LESSOR’s last designated address. No oral notice or representation shall have any force or effect. Time is of the essence in the service of any notice.