ADTRAN (ADTN) 8-KCompletion of Acquisition or Disposition of Assets

Exhibit 3.1

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

ACORN HOLDCO, INC.

July 7, 2022

Acorn HoldCo, Inc., a corporation organized and existing under the laws of the State of Delaware (the “Corporation”), hereby certifies as follows:

FIRST: The name of the Corporation is Acorn HoldCo, Inc. and the Corporation was originally incorporated pursuant to the General Corporation Law of the State of Delaware (the “DGCL”) on August 10, 2021.

SECOND: The board of directors of the Corporation duly adopted a resolution proposing to amend and restate the Certificate of Incorporation of this Corporation, declaring said amendment and restatement in the form attached hereto as Exhibit A (the “Restated Certificate”) to be advisable and in the best interests of the Corporation and its stockholders, and authorizing the appropriate officers of this Corporation to solicit the consent of the stockholders of the Corporation to the Restated Certificate in accordance with the DGCL.

THIRD: The Restated Certificate was approved by the holders of the requisite number of shares of this Corporation in accordance with Section 228 of the DGCL.

FOURTH: The Restated Certificate, which restates in its entirety the provisions of this Corporation’s Certificate of Incorporation, has been duly adopted in accordance with Sections 242 and 245 of the DGCL.

IN WITNESS WHEREOF, the undersigned, for the purpose of restating and integrating and further amending the Certificate of Incorporation pursuant to the DGCL, does hereby declare and certify that this is the act and deed of the Corporation and the facts stated herein are true, and accordingly has hereunto signed this Certificate of the Corporation’s Amended and Restated Certificate of Incorporation this 7th day of July, 2022.

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EXHIBIT A

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

ADTRAN HOLDINGS, INC.

ARTICLE I

Section 1.1 Name. The name of the Corporation is ADTRAN Holdings, Inc. (the “Corporation”).

ARTICLE II

Section 2.1 Address. The address of its registered office of the Corporation in the State of Delaware is Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801, County of New Castle. The name of its registered agent at such address is The Corporation Trust Company.

ARTICLE III

Section 3.1 Purpose. The nature of the business or purposes to be conducted or promoted is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware (the “DGCL”).

ARTICLE IV

Section 4.1 Authorized Capital. The total number of shares of stock which the Corporation shall have the authority to issue is Two Hundred Million (200,000,000) shares of common stock, par value $0.01 per share (“Common Stock”), and Fifty Million (50,000,000) shares of preferred stock, par value $0.01 per share (“Preferred Stock”).

Section 4.2 Common Stock.

(a) Voting Rights. Except as otherwise provided in this Certificate of Incorporation or otherwise required by applicable law, each holder of Common Stock shall be entitled to one vote for each share of Common Stock held as of the applicable record date on any matter that is submitted to a vote or for the consent of the stockholders of the Corporation.

(b) Dividends. Subject to the preferences applicable to any series of Preferred Stock, if any, outstanding at any time, the holders of Common Stock shall be entitled to share equally, on a per share basis, in such dividends and other distributions of cash, property or shares of stock of the Corporation as may be declared by the Board of Directors of Directors of the Corporation (the “Board of Directors”) from time to time with respect to the Common Stock out of assets or funds of the Corporation legally available therefor.

(c) Liquidation. Subject to the preferences applicable to any series of Preferred Stock, if any, outstanding at any time, in the event of the voluntary or involuntary liquidation, dissolution, distribution of assets or winding up of the Corporation, all assets of the Corporation of whatever kind available for distribution to the holders of Common Stock shall be divided among and paid ratably to the holders of Common Stock.

Section 4.3 Preferred Stock.

(a) Preferred Stock may be issued from time to time by the Corporation for such consideration as may be fixed by the Board of Directors. The Board of Directors is hereby expressly authorized, by resolution or resolutions, to provide, out of the unissued shares of Preferred Stock, for one or more series of Preferred Stock and, with respect to each such series, to fix, without further stockholder approval, the designation of such series, the powers (including voting powers), preferences and relative, participating, optional and other special rights, and the qualifications, limitations or restrictions thereof, of such series of Preferred Stock and the number of shares of such series, and as may be permitted by the DGCL. The powers, preferences and relative, participating, optional and other special rights of, and the qualifications, limitations or restrictions thereof, each series of Preferred Stock, if any, may differ from those of any and all other series at any time outstanding.

(b) Except as otherwise required by law, holders of Common Stock shall not be entitled to vote on any amendment to this Certificate of Incorporation (including any certificate of designation relating to any series of Preferred Stock) that relates solely to the terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to this Certificate of Incorporation (including any certificate of designation relating to any series of Preferred Stock) or pursuant to the DGCL.

(c) Except as otherwise required by law, holders of any series of Preferred Stock shall be entitled to only such voting rights, if any, as shall expressly be granted thereto by this Certificate of Incorporation (including any certificate of designation relating to such series of Preferred Stock).

ARTICLE V

Section 5.1 Board of Directors.

(a) Except as otherwise provided in this Certificate of Incorporation or the DGCL, the business and affairs of the Corporation shall be managed by or under the direction of the Board of Directors.

(b) Notwithstanding any other provision of this Article V, and except as otherwise required by law, whenever the holders of one or more series of Preferred Stock shall have the right, voting separately by class or series, to elect one or more directors, the term of office, the filling of vacancies, the removal from office and other features of such directorships shall be governed by the terms of such series of Preferred Stock as set forth in this Certificate of Incorporation (including any preferred stock designation).

(c) In furtherance and not in limitation of the powers conferred by statute, the Board of Directors is expressly authorized:

(1) To make, amend, alter, change, add to or repeal, in whole or in part, the Bylaws of the Corporation (the “Bylaws”) without the assent or vote of the stockholders in any manner not inconsistent with the laws of the State of Delaware or this Certificate of Incorporation.

(2) To authorize and cause to be executed mortgages and liens upon the real and personal property of the Corporation.

(3) To set apart out of any of the funds of the Corporation available for dividends a reserve or reserves for any proper purpose and to abolish any such reserve in the manner in which it was created.

(4) By a majority of the whole Board of Directors, to designate one or more committees, each committee to consist of two or more of the directors of the Corporation. The Board of Directors may designate one or more directors as alternate members of any committee, who may replace any absent or disqualified member at any meeting of the committee. Any such committee, to the extent provided in the resolution or in the by-laws of the Corporation, shall have and may exercise the powers of the Board of Directors in the management of the business and affairs of the Corporation, and may authorize the seal of the Corporation to be affixed to all papers which may require it; provided, however, the by-laws may provide that in the absence or disqualification of any member of such committee or committees, the member or members thereof present at any meeting and not disqualified from voting, whether or not he or they constitute a quorum, may unanimously appoint another member of the Board of Directors to act at the meeting in the place of any such absent or disqualified member.

(5) When and as authorized by the affirmative vote of the holders of a majority of the stock issued and outstanding having voting power given at a stockholders’ meeting duly called upon such notice as is required by statute, or when authorized by the written consent of the holders of a majority of the voting stock issued and outstanding, to sell, lease or exchange all or substantially all of the property and assets of the Corporation, including its good will and its corporate franchises, upon such terms and conditions and for such consideration, which may consist in whole or in part of money or property including shares of stock in, and/or other securities of, any other corporation or corporations, as its Board of Directors shall deem expedient and for the best interests of the Corporation.

(d) Preferred Stock—Directors. Notwithstanding any other provision of this Article V, and except as otherwise required by law, whenever the holders of one or more series of Preferred Stock shall have the right, voting separately by class or series, to elect one or more directors, the term of office, the filling of vacancies, the removal from office and other features of such directorships shall be governed by the terms of such series of Preferred Stock as set forth in this Certificate of Incorporation (including any preferred stock designation).

ARTICLE VI

Section 6.1 Meetings of Stockholders. Meetings of stockholders may be held within or without the State of Delaware, as the Bylaws may provide. The books of the Corporation may be kept (subject to applicable law) outside the State of Delaware at such place or places as may be designated from time to time by the Board of Directors or in the Bylaws of the Corporation. Elections of directors need not be by written ballot unless the Bylaws of the Corporation shall so provide.

Section 6.2 Action by Written Consent. Any corporate action upon which a vote of stockholders is required or permitted may be taken with the written consent of stockholders having not less than a majority of all of the stock entitled to vote upon the action if a meeting were held; provided that in no case shall the written consent be by holders having less than the minimum percentage of the vote required by statute for the proposed corporate action and provided that prompt notice be given to all stockholders of the taking of corporate action without a meeting and by less than unanimous written consent.

ARTICLE VII

Section 7.1 Limitation of Liability. (a) No person shall be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director; provided, however, that the foregoing shall not eliminate or limit the liability of a director (i) for any breach of the director’s duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the DGCL or (iv) for any transaction from which the director derived an improper personal benefit. If the DGCL is subsequently amended to further eliminate or limit the liability of a director,

then a director of the Corporation, in addition to the circumstances in which a director is not personally liable as set forth in the preceding sentence, shall not be liable to the fullest extent permitted by the amended DGCL. For purposes of this Article VII, “fiduciary duty as a director” also shall include any fiduciary duty arising out of serving at the Corporation’s request as a director of another corporation, partnership, joint venture or other enterprise, and “personal liability to the Corporation or its stockholders” also shall include any liability to such other corporation, partnership, joint venture, trust or other enterprise, and any liability to the Corporation in its capacity as a security holder, joint venturer, partner, beneficiary, creditor or investor of or in any such other corporation, partnership, joint venture, trust or other enterprise.

Any repeal or modification of Section 7.1 of this Article VII by the stockholders of the Corporation shall not adversely affect any right or protection of a director of the Corporation existing at the time of such repeal or modification.

ARTICLE VIII

Section 8.1 Indemnification. Each person who was or is made a party or is threatened to be made a party to or is involved in any action, suit or proceeding, whether civil, criminal, administrative or investigative (hereinafter a “proceeding”), by reason of the fact that he or she, or a person of whom he or she is the legal representative, is or was a director or officer of the Corporation or is or was serving at the request of the Corporation as a director or officer of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to employee benefit plans, whether the basis of such proceeding is alleged action in an official capacity as a director or officer or in any other capacity while serving as a director or officer shall be indemnified and held harmless by the Corporation to the fullest extent authorized by the DGCL, as the same exists or may hereafter be amended (but, in the case of any such amendment, only to the extent that such amendment permits the Corporation to provide broader indemnification rights than said law permitted the Corporation to provide prior to such amendment), against all expense, liability and loss (including attorneys’ fees, judgments, fines, ERISA excise taxes or penalties and amounts to be paid in settlement) reasonably incurred or suffered by such person in connection therewith, and such indemnification shall continue as to a person who has ceased to be a director or officer and shall inure to the benefit of his or her heirs, executors and administrators; provided, however, that except as provided in this Section 8.1 with respect to proceedings seeking to enforce rights to indemnification, the Corporation shall indemnify any such person seeking indemnification in connection with a proceeding (or part thereof) initiated by such person only if such proceeding (or part thereof) was authorized by the Board of Directors of the Corporation. Further, the Corporation also may indemnify and hold harmless employees and agents of the Corporation to the fullest extent authorized by the DGCL, as the same exists or may hereafter be amended (but, in the case of any such amendment, only to the extent such amendment permits the Corporation to provide broader indemnification rights than said law permitted the Corporation to provide prior to such amendment), and such discretionary authority to indemnify employees and agents of the Corporation shall be vested in, and may be exercised by, the Board of Directors of the Corporation; provided, however, that the Board of Directors of the Corporation shall have no discretionary authority relative to the indemnification of an employee or agent of the Corporation where the DGCL specifically provides that indemnification is mandatory. The right to indemnification conferred in this Article relative to directors and officers of the Corporation shall be a contract right and shall include the right to be paid by the Corporation the expenses incurred in defending any such proceeding in advance of its final disposition; provided, however, that, if the DGCL requires, the payment of such expenses incurred by a director or officer in his or her capacity as a director or officer (and not in any other capacity in which service was or is rendered by such person while a director or officer, including, without limitation, service to an employee benefit plan) in advance of the final disposition of a proceeding shall be made only upon delivery to the Corporation of an undertaking, by or on behalf of such director or officer, to repay all amounts so advanced if it shall ultimately be determined that such director or officer is not entitled to be indemnified under this Article VIII or otherwise.

Section 8.2 Payment of Mandatorily Indemnified Claims. If a claim relative to which a director, officer, employee or agent is entitled to be mandatorily indemnified under Section 8.1 is not paid in full by the Corporation within ninety days after a written claim has been received by the Corporation, the claimant may at any time thereafter bring suit against the Corporation to recover the unpaid amount of the claim and, if successful in whole or in part, the claimant also shall be entitled to be paid the expense of prosecuting such claim. It shall be a defense to any such action (other than an action brought to enforce a claim for expenses incurred in defending any proceeding in advance of its final disposition where the required undertaking, if any is required, has been tendered to the Corporation) that the

claimant has not met the standards of conduct which make it permissible under the DGCL for the Corporation to indemnify the claimant for the amount claimed, but the burden of proving such defense shall be on the Corporation. Neither the failure of the Corporation (including its Board of Directors, independent legal counsel or stockholders) to have made a determination prior to the commencement of such action that indemnification of the claimant is proper in the circumstances because he or she has met the applicable standard of conduct set forth in the DGCL, nor an actual determination by the Corporation (including its Board of Directors, independent legal counsel or stockholders) that the claimant has not met such applicable standard of conduct shall be a defense to the action or create a presumption that the claimant has not met the applicable standard of conduct.

Section 8.3 Non-Exclusivity. The right to indemnification and the payment of expenses incurred in defending a proceeding in advance of its final disposition conferred in this Article VIII shall not be exclusive of any other right which any person may have or hereafter acquire under any statute, provision of the Certificate of Incorporation, bylaws, agreement, vote of stockholders or disinterested directors or otherwise.

Section 8.4 Insurance. The Corporation may maintain insurance, at its expense, to protect itself and any director, officer, employee or agent of the Corporation or another corporation, partnership, joint venture, trust or other enterprise against any expense, liability or loss, whether or not the Corporation would have the power to indemnify such person against such expense, liability or loss under the DGCL.

ARTICLE IX

Section 9.1 Severability. If any provision or provisions of this Certificate of Incorporation shall be held to be invalid, illegal or unenforceable as applied to any circumstance for any reason whatsoever: (i) the validity, legality and enforceability of such provisions in any other circumstance and of the remaining provisions of this Certificate of Incorporation (including, without limitation, each portion of any paragraph of this Certificate of Incorporation containing any such provision held to be invalid, illegal or unenforceable that is not itself held to be invalid, illegal or unenforceable) shall not, to the fullest extent permitted by applicable law, in any way be affected or impaired thereby and (ii) to the fullest extent permitted by applicable law, the provisions of this Certificate of Incorporation (including, without limitation, each such portion of any paragraph of this Certificate of Incorporation containing any such provision held to be invalid, illegal or unenforceable) shall be construed so as to permit the Corporation to protect its directors, officers, employees and agents from personal liability in respect of their good faith service to or for the benefit of the Corporation to the fullest extent permitted by law.

ARTICLE X

Section 10.1 Forum: Court of Chancery. Unless the Corporation selects or consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or, if and only if the Court of Chancery does not have subject matter jurisdiction, another state court sitting in the State of Delaware or, if and only if neither the Court of Chancery nor any state court sitting in the State of Delaware has subject matter jurisdiction, then the federal district court for the District of Delaware) shall, to the fullest extent permitted by law, be the sole and exclusive forum for (1) any derivative action or proceeding brought on behalf of the Corporation, (2) any action asserting a claim of breach of a fiduciary duty owed by any director, officer, or other employee or stockholder of the Corporation to the Corporation or the Corporation’s stockholders, creditors or other constituents, or a claim of aiding and abetting any such breach of fiduciary duty, (3) any action asserting a claim against the Corporation or any director or officer of the Corporation arising pursuant to any provision of the DGCL or this Certificate of Incorporation or the Bylaws (as either may be amended and/or restated from time to time) or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware, (4) any action to interpret, apply, enforce or determine the validity of this Certificate of Incorporation or the Bylaws, (5) any action asserting a claim against the Corporation or any director or officer of the Corporation governed by the internal affairs doctrine or (6) any other action asserting an “internal corporate claim” as that term is defined in Section 115 of the DGCL.

Section 10.2 Forum: Federal District Courts. Unless the Corporation selects or consents in writing to the selection of an alternative forum, the federal district courts of the United States shall be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under federal securities laws against the Corporation or any director or officer of the Corporation.

Section 10.3 Consent to Forum. To the fullest extent permitted by law, any person or entity purchasing or otherwise acquiring or holding any interest in shares of capital stock of the Corporation shall be deemed to have notice of and consented to the provisions of this Article X and personal jurisdiction and venue in any state or federal court located in the State of Delaware for any action or proceeding set forth in above clauses 1 to 6 of Section 10.1 and any complaint set forth in Section 10.2.

ARTICLE XI

Section 11.1 Amendments. The Corporation reserves the right to amend, alter, change or repeal any provision contained in this Certificate of Incorporation, and other provisions authorized by the laws of the State of Delaware at the time in force may be added or inserted, in the manner now or hereafter prescribed by the laws of the State of Delaware, and all rights, preferences and privileges of whatsoever nature conferred upon stockholders, directors or any other person whomsoever by and pursuant to this Certificate of Incorporation in its present form or as hereafter amended are granted subject to this reservation.

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This Amended and Restated Certificate of Incorporation shall be effective on July 8, 2022 at 6:59 a.m. Eastern Time.