All notices and other communications pertaining to this Agreement shall be in writing and shall be deemed duly to have been given if personally delivered to the other Party or if sent by certified mail, return receipt requested, postage prepaid or by Federal Express, United Parcel or other nationally recognized overnight carrier. All notices or communications between Purchaser and Vendor pertaining to this Agreement shall be addressed to the Vendor at: joekalfa@gmail.com and to the Purchaser at john@riotblockchain.com and to the Escrow Agent at shira@rktaxlaw.com. Either Party may change its notification address by giving written notice to that effect to the other Party in the manner provided herein.