Index: src/wp-content/themes/twentyseventeen/inc/icon-functions.php
===================================================================
--- src/wp-content/themes/twentyseventeen/inc/icon-functions.php	(revision 39164)
+++ src/wp-content/themes/twentyseventeen/inc/icon-functions.php	(working copy)
@@ -102,7 +102,7 @@
 	 *
 	 * See https://core.trac.wordpress.org/ticket/38387.
 	 */
-	$svg .= ' <use xlink:href="#icon-' . esc_html( $args['icon'] ) . '"></use> ';
+	$svg .= ' <use href="#icon-' . esc_html( $args['icon'] ) . '" xlink:href="#icon-' . esc_html( $args['icon'] ) . '"></use> ';
 
 	// Add some markup to use as a fallback for browsers that do not support SVGs.
 	if ( $args['fallback'] ) {