Your Vote Counts!Get informed before you voteView the Notice of Proxy Statement, Annual Report,1234567890123456789012345678901234567890, 1234567890123456789012345678901234567890, 1234567890123456789012345678901234567890, 1234567890123456789012345678901234567890 online OR you can receive a free paper copy of voting material(s) by requesting prior to <matcutoff>. If you would like to request a copy of the voting material(s), you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Smartphone usersPoint your camera here and vote without entering a control number For complete information and to vote, visit www.ProxyVote.com Control # FLASHID-JOB# Ricky CampanaP.O. Box 123456Suite 50051 Mercedes WayEdgewood, NY 117171 OF 2322,224148,29430# XXXX XXXX XXXX XXXX DIGI INTERNATIONAL INC. 2023 Annual Meeting Vote by January 26, 2023 11:59 PM ET DIGI INTERNATIONAL INC. ATTN: OFFICE OF GENERAL COUNSEL 9350 EXCELSIOR BLVD., SUITE 700 HOPKINS, MN 55343 You invested in DIGI INTERNATIONAL INC. and it's time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on January 27, 2023. View the Notice & Proxy Statement, Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to January 13, 2023. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. Vote Virtually at the Meeting* January 27, 2023 3:30 PM CST Virtually at: www.virtualshareholdermeeting.com/DGII2023 *Please check the meeting materials for any special requirements for meeting attendance.

THIS IS NOT A VOTABLE BALLOTThis is an overview of the proposals being presented at the upcoming shareholder meeting. Please follow the instructions on the reverse side to vote these important matters. Vote at www.ProxyVote.com Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”. Voting ItemsBoard RecommendsFLASHID-JOB#Control # XXXX XXXX XXXX XXXXTHE COMPANY NAME INC. - COMMON ASDFGHJKL 123456789.1234THE COMPANY NAME INC. - CLASS A 123456789.1234THE COMPANY NAME INC. - CLASS B 123456789.1234THE COMPANY NAME INC. - CLASS C 123456789.1234THE COMPANY NAME INC. - CLASS D 123456789.1234THE COMPANY NAME INC. - CLASS E 123456789.1234THE COMPANY NAME INC. - CLASS F 123456789.1234THE COMPANY NAME INC. - 401 K 123456789.1234SHARE CLASSES REPRESENTED FOR VOTING This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. 1. Election of Directors Nominees: 1a. Satbir Khanuja, Ph.D. For 1b. Ronald E. Konezny For 2. Company proposal to approve, on a non-binding advisory basis, the compensation paid to named executive officers. For 3. Company proposal to ratify the appointment of Deloitte & Touche LLP as independent registered public accounting firm of the company for the fiscal year ending September 30, 2023. For 4. Company proposal to approve the amendment and restatement of the Digi International Inc. 2021 Omnibus Incentive Plan. For NOTE: If any other matters properly come before the annual meeting calling for a vote of stockholders, the shares represented by this proxy will be voted by the persons named herein in accordance with their best judgment.