JOINDER AND AMENDMENT NO. 2 TO AMENDED AND RESTATEDSHAREHOLDERS AGREEMENT AND REGISTRATION AGREEMENT

Exhibit 10.27

JOINDER AND AMENDMENT NO. 2 TO

AMENDED AND RESTATED SHAREHOLDERS AGREEMENT AND

REGISTRATION AGREEMENT

THIS JOINDER AND AMENDMENT NO. 2 TO AMENDED AND RESTATED SHAREHOLDERS AGREEMENT AND REGISTRATION AGREEMENT (this “Amendment”) is made as of September 22, 2005, by and among Aspect Software Group Holdings Ltd. (f/k/a Concerto Software Group Holdings Ltd.), a company organized under the laws of the Cayman Islands (the “Company”), the investment funds managed by Golden Gate Capital listed on the signature pages hereto and the investment funds managed by Oak Investment Partners listed on the signature pages hereto.

Reference is made to (i) that certain Amended and Restated Shareholders Agreement, dated as of February 9, 2004 (the “Shareholders Agreement”), by and among the Company and the Persons listed on Schedules I, II and III attached thereto, as amended and (ii) that certain Registration Agreement (the “Registration Agreement”), dated as of February 9, 2004, by and among the Company and the Persons listed on Schedules I, II and III attached thereto, as amended.

The parties hereto desire to amend the Shareholders Agreement in certain respects and join certain persons as a party to the Shareholders Agreement and the Registration Agreement as of the date hereof, in each case as hereinafter provided.

NOW, THEREFORE, the parties to this Amendment hereby agree as follows:

1. Amendment of Shareholders Agreement. Pursuant to Section 11 of the Shareholders Agreement, the Shareholders Agreement is hereby amended as follows:

(a) By deleting Sections 1(a) and 1(b) of the Shareholders Agreement in their entirety and replacing them with the following:

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(b) By adding the following sentence to Section 4(b) of the Shareholders Agreement:

Notwithstanding the foregoing, in the event of an Approved Sale, the members of the Oak Group shall not be required to make any representations, warranties or covenants regarding the business or affairs of the Company or any of its Subsidiaries and shall not be required to give any indemnifications more onerous than indemnifications provided by other shareholders in such Approved Sale or in an amount exceeding the net proceeds distributable to the members of the Oak Group from such Approved Sale.

(c) By deleting Section 2(b) of the Shareholders Agreement and replacing it with the following:

(b) Certain Permitted Transfers. The restrictions contained in Section 2(a) will not apply to any Transfer of Shareholder Shares by any Shareholder (i) among its Affiliates, (ii) pursuant to Section 4 or a Change in Control, (iii) pursuant to Section 5, (iv) pursuant to the applicable laws of descent and distribution or among such Shareholder’s Family Group, (v) pursuant to Section 3 hereof or (vi) to the Company or any of its Subsidiaries; provided that the restrictions contained in this Agreement will continue to apply to the Shareholder Shares after any Transfer pursuant to clause (i), (iv) or (v) above and each transferee of such Shareholder Shares shall agree in writing, prior to and as a condition to the effectiveness of such Transfer, to be bound by the provisions of this Agreement, without modification or condition, subject only to the consummation of the Transfer. Upon the Transfer of Shareholder Shares pursuant to this Section 2(b), the transferor will deliver a written notice to the Company and the other parties to this Agreement, which notice will disclose in reasonable detail the identity of such transferee(s) and shall include an original counterpart of the agreement of such transferee(s) to be bound by this Agreement.

(d) By deleting Section 8 of the Shareholders Agreement and replacing it with the following:

8. Transfer. Prior to Transferring any Shareholder Shares (other than in a Public Sale permitted pursuant to the terms and conditions of this Agreement, in an Approved Sale or pursuant to any Transfer permitted by clause (vi) of Section 2(b)) to any Person, the transferring Shareholder shall cause the prospective transferee to execute and deliver to the Company and the other Shareholders a counterpart of this Agreement and thereafter all references to the transferring Shareholder shall be deemed to refer to the transferee and all references to the transferring Shareholder’s Group shall be deemed to include the transferee. The provisions of this Section 8 will terminate upon the earlier to occur of (i) the consummation of a Change in Control and (ii) the consummation of an IPO.

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2. Addition of Certain Parties to the Shareholders Agreement.

(a) The parties hereto agree that, by and upon execution of this Amendment, Oak Investment Partners XI, Limited Partnership (“Oak XI”) (i) shall be a party to the Shareholders Agreement, (ii) accepts and agrees to be subject to all terms, conditions and obligations of the Shareholders Agreement as a holder of Oak Shares, (iii) shall be considered a member of the “Oak Group” and a holder of “Oak Shares” thereunder and (iv) shall be entitled to the rights and benefits and subject to the duties and obligations of a member of the Oak Group and a holder of Oak Shares thereunder, as applicable, in each case as fully as if Oak XI were an original signatory thereto in such capacities. Schedule II attached to the Shareholders Agreement is hereby amended to add Oak XI thereto.

(b) The parties hereto agree that, by and upon execution of this Amendment, each of the persons listed on Schedule 1 attached hereto (each, a “New Golden Gate Party”) (i) shall be a party to the Shareholders Agreement, (ii) accepts and agrees to be subject to all terms, conditions and obligations of the Shareholders Agreement as a holder of Golden Gate Shares, (iii) shall be considered a member of the “Golden Gate Group” and a holder of “Golden Gate Shares” thereunder and (iv) shall be entitled to the rights and benefits and subject to the duties and obligations of a member of the Golden Gate Group and a holder of Golden Gate Shares thereunder, as applicable, in each case as fully as if such New Golden Gate Party were an original signatory thereto in such capacities. Schedule II attached to the Shareholders Agreement is hereby amended to add each New Golden Gate Party thereto.

3. Addition of Certain Parties to the Registration Agreement.

(a) The parties hereto agree that, by and upon execution of this Amendment, Oak XI (i) shall be a party to the Registration Agreement, (ii) accepts and agrees to be subject to all terms, conditions and obligations of the Registration Agreement as a holder of Oak Registrable Securities, (iii) shall be considered an “Oak Shareholder” and a holder of “Oak Registrable Securities” thereunder and (iv) shall be entitled to the rights and benefits and subject to the duties and obligations of an Oak Shareholder and a holder of Oak Registrable Securities thereunder, as applicable, in each case as fully as if Oak XI were an original signatory thereto in such capacities. Schedule II attached to the Shareholders Agreement is hereby amended to add Oak XI thereto.

(b) The parties hereto agree that, by and upon execution of this Amendment, each New Golden Gate Party (i) shall be a party to the Registration Agreement, (ii) accepts and agrees to be subject to all terms, conditions and obligations of the Registration Agreement as a holder of Golden Gate Registrable Securities, (iii) shall be considered a “Golden Gate Shareholder” and a holder of “Golden Gate Registrable Securities” thereunder and (iv) shall be entitled to the rights and benefits and subject to the duties and obligations of a Golden Gate Shareholder and a holder of Golden Gate Registrable Securities thereunder, as applicable, in each case as fully as if such New Golden Gate Party were an original signatory thereto in such capacities. Schedule I attached to the Shareholders Agreement is hereby amended to add each New Golden Gate Party.

4. Continuing Effect. Except as expressly provided herein, this Amendment shall not constitute an amendment, modification or waiver of any provision of the Shareholders Agreement or the Registration Agreement, which shall continue and remain in full force and effect in accordance with its terms (as amended hereby).

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5. Severability. Whenever possible, each provision of this Amendment shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Amendment is held to be invalid, illegal or unenforceable in any respect under any applicable law or rule in any jurisdiction, such invalidity, illegality or unenforceability shall not affect any other provision or the effectiveness or validity of any provision in any other jurisdiction, and this Agreement shall be reformed, construed and enforced in such jurisdiction as if such invalid, illegal or unenforceable provision had never been contained herein.

6. Counterparts. This Agreement may be executed in one or more counterparts each of which shall be an original and all of which taken together shall constitute one and the same agreement.

7. Delivery by Facsimile. This Amendment and any signed agreement or instrument entered into in connection herewith or contemplated hereby, and any amendments hereto or thereto, to the extent signed and delivered by means of a facsimile machine, shall be treated in all manner and respects as an original agreement or instrument and shall be considered to have the same binding legal effect as if it were the original signed version thereof delivered in person. At the request of any party hereto or to any such agreement or instrument, each other party hereto or thereto shall re-execute original forms thereof and deliver them to all other parties. No party hereto or to any such agreement or instrument shall raise the use of a facsimile machine to deliver a signature or the fact that any signature or agreement or instrument was transmitted or communicated through the use of a facsimile machine as a defense to the formation of a contract and each such party forever waives any such defense.

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IN WITNESS WHEREOF, the parties hereto have executed this Joinder and Amendment No. 2 to Amended and Restated Shareholders Agreement and Registration Agreement on the day and year first above written.

[Signature Page to Shareholders Agreement]

[Signature Page to Shareholders Agreement]

[Signature Page to Shareholders Agreement]

SCHEDULE 1

New Golden Gate Parties

Golden Gate Capital Investment Fund II, LP

Golden Gate Capital Investment Fund II-A, LP

Golden Gate Capital Investment Fund II (AI), LP

Golden Gate Capital Investment Fund II-A (AI), LP

Golden Gate Capital Associates II-QP, LLC

Golden Gate Capital Associates II-AI, LLC