X0206 3 2022-07-08 0 0000926282 ADTRAN Holdings, Inc. ADTN 0001191219 STANTON THOMAS R C/O ADTRAN HOLDINGS, INC. 901 EXPLORER BLVD. HUNTSVILLE AL 35806 1 1 0 0 Chairman, CEO and President No securities are beneficially owned 0 D Immediately following the Effective Time (as defined in that certain Business Combination Agreement dated as of August 30, 2021, by and among ADTRAN, Inc., ADVA Optical Networking SE, the Issuer (f/k/a Acorn HoldCo, Inc.), and Acorn MergeCo, Inc.), the reporting person became an executive officer and a member of the Board of Directors of the Issuer. /s/ Michael Foliano, by power of attorney 2022-07-11