All notices, demands requests, consents, approvals, and other communications required or permitted hereunder shall be in writing and, unless otherwise specified herein, shall be (i) personally served, (ii) deposited in the mail, registered or certified, return receipt requested, postage prepaid, (iii) delivered by reputable air courier service with charges prepaid, or (iv) transmitted by hand delivery, addressed as set forth below or to such other address as such party shall have specified most recently by written notice. The addresses for such communications shall be: (i) if to the Company, to: GT Biopharma, Inc., Attn: Chief Financial Officer, 4100 South Ashley Drive, Suite 600, Tampa, FL 33602, and (ii) if to the Warrant Holders, to the addresses as indicated on the signature pages attached hereto.