BELL CANADA and BCE INC. and BNY TRUST COMPANY OF CANADA– COMPAGNIE TRUST BNY CANADA (Trustee) FOURTH SUPPLEMENTAL TRUST INDENTURE Dated as of August 6, 2021

Exhibit 99.1

▇▇▇▇ CANADA

and

BCE INC.

and

BNY TRUST COMPANY OF CANADA–

COMPAGNIE TRUST BNY CANADA

(Trustee)

FOURTH SUPPLEMENTAL

TRUST INDENTURE

Dated as of August 6, 2021

FOURTH SUPPLEMENTAL TRUST INDENTURE

This FOURTH SUPPLEMENTAL TRUST INDENTURE, made as of August 6, 2021 (the “Fourth Supplemental Trust Indenture”).

RECITALS :

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NOW THEREFORE THIS FOURTH SUPPLEMENTAL TRUST INDENTURE WITNESSETH and it is hereby covenanted, agreed and declared as follows:

ARTICLE 1

Indenture Supplemental

to the Original Trust Indenture

Section 1.01    Part of Original Trust Indenture – This Fourth Supplemental Trust Indenture is declared to be supplemental to the Original Trust Indenture and is to form part of and shall have the same effect as though incorporated in the Original Trust Indenture, subject to Section 2.01 below. The Original Trust Indenture is a part of these presents and is by this reference included herein with the same effect as though at length set forth herein.

Section 1.02    Capitalized Terms – All capitalized terms contained in this Fourth Supplemental Trust Indenture (including the Recitals hereto) unless otherwise defined herein, shall, for all purposes hereof, have their respective meanings as set out in the Original Trust Indenture, unless expressly stated otherwise or the context otherwise requires.

ARTICLE 2

Resignation and Replacement

of Trustee

Section 2.01    Notice of Resignation– CIBC Mellon hereby provides notice to the Corporation of its intention to resign as indenture trustee and registrar under the Original Trust Indenture effective as of the date hereof.

Section 2.02    Resignation and Replacement of Trustee – In accordance with the Original Trust Indenture, CIBC Mellon hereby resigns as indenture trustee and registrar and shall not be responsible for any obligations or liabilities relating to or arising in respect of the Original Trust Indenture on or after the date hereof.

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Section 2.03    Appointment of BNY – The Corporation hereby accepts CIBC Mellon’s resignation and hereby appoints BNY as the successor indenture trustee and registrar under the Original Trust Indenture.

Section 2.04    Acceptance by BNY – BNY hereby accepts the appointment as the Trustee pursuant to Section 6.10 of the Original Trust Indenture and as registrar under the Original Trust Indenture effective as of the date hereof, and agrees (i) to be bound by and to perform, all obligations and liabilities of CIBC Mellon as indenture trustee and registrar under the Original Trust Indenture, arising on and after the date hereof, and (ii) to be vested with the same powers, rights, duties and obligations as if it had originally been named in the Original Trust Indenture as indenture trustee and registrar.

Section 2.05    Representations and Warranties – BNY hereby represents and warrants to the Corporation the following:

ARTICLE 3

Confirmation

Section 3.01    Original Trust Indenture – The Corporation, the Guarantor and the Trustee hereby acknowledge and confirm that, except as specifically supplemented, modified or changed by the provisions of this Fourth Supplemental Trust Indenture, all of the terms and conditions contained in the Original Trust Indenture (as previously supplemented, modified or changed) are and shall remain in force and effect, unamended, in accordance with the provisions thereof. The matters provided for in this Fourth Supplemental Trust Indenture shall not prejudice any act or thing done prior to the date hereof and do not constitute novation.

Section 3.02    Applicable Law – This Fourth Supplemental Trust Indenture, all acts and transactions hereunder, and the rights and obligations of the parties hereto, shall be governed, construed and interpreted in accordance with the laws of the Province of Québec and the laws of Canada applicable therein.

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ARTICLE 4

Guarantee

Section 4.01    Confirmation of Guarantee – The Guarantor agrees that the Guarantee provided by the Guarantor pursuant to the Second Supplemental Trust Indenture to the Original Trust Indenture:

ARTICLE 5

Execution

Section 5.01    Counterparts and Formal Date – This Fourth Supplemental Trust Indenture may be executed in several counterparts, deliverable by electronic means, each of which so executed shall be deemed to be an original, and such counterparts together shall constitute one and the same instrument and notwithstanding their date of execution shall be deemed to bear the date first written hereinabove. For certainty, this Fourth Supplemental Trust Indenture may be executed by way of electronic signature (including through an information system such as DocuSign or by any other electronic means) and any such execution shall be of the same legal effect, validity or enforceability as a manually executed signature.

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IN WITNESS WHEREOF, the parties hereto have declared that they have required that these presents be in the English language and have executed these presents as of the date first written above.