EXHIBIT NO. 99.(a) 35

MFS SERIES TRUST X

CERTIFICATION OF AMENDMENT

TO THE DECLARATION OF TRUST

TERMINATION OF CLASS

Pursuant to Section 9.2(b) of the Amended and Restated Declaration of Trust, dated as of December 16, 2004, as amended (the “Declaration”), of MFS Series Trust X, a business trust organized under the laws of The Commonwealth of Massachusetts (the “Trust”), the undersigned, constituting a majority of the Trustees of the Trust, do hereby certify that Class T Shares of MFS Emerging Markets Debt Local Currency Fund, a series of the Trust, have been terminated effective upon the filing of this instrument with the Secretary of State of The Commonwealth of Massachusetts.

IN WITNESS WHEREOF, a majority of the Trustees of the Trust have executed this amendment, in one or more counterparts, all constituting a single instrument, as an instrument under seal in The Commonwealth of Massachusetts, as of February 12, 2020 and further certify, as provided by the provisions of Section 9.3(c) of the Declaration, that this amendment was duly adopted by the undersigned in accordance with Section 9.3(a) of the Declaration.

STEVEN E. BULLER	JAMES W. KILMAN, JR.
Steven E. Buller	James W. Kilman, Jr.
c/o MFS Investment Management	c/o MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199
JOHN A. CAROSELLI	ROBERT J. MANNING
John A. Caroselli	Robert J. Manning
c/o MFS Investment Management	MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199
MAUREEN R. GOLDFARB	CLARENCE OTIS, JR.
Maureen R. Goldfarb	Clarence Otis, Jr.
c/o MFS Investment Management	MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199
MICHAEL HEGARTY	MARYANNE L. ROEPKE
Michael Hegarty	Maryanne L. Roepke
c/o MFS Investment Management	c/o MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199
PETER D. JONES	ROBIN A. STELMACH
Peter D. Jones	Robin A. Stelmach
c/o MFS Investment Management	MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199
JOHN P. KAVANAUGH	LAURIE J. THOMSEN
John P. Kavanaugh	Laurie J. Thomsen
c/o MFS Investment Management	c/o MFS Investment Management
111 Huntington Avenue	111 Huntington Avenue
Boston, MA 02199	Boston, MA 02199