diff --git a/core/modules/file/src/Tests/FileFieldRSSContentTest.php b/core/modules/file/src/Tests/FileFieldRSSContentTest.php
index 7f04ac2..56400a8 100644
--- a/core/modules/file/src/Tests/FileFieldRSSContentTest.php
+++ b/core/modules/file/src/Tests/FileFieldRSSContentTest.php
@@ -68,15 +68,12 @@ function testFileFieldRSSContent() {
     // Check that the RSS enclosure appears in the RSS feed.
     $this->drupalGet('rss.xml');
     $uploaded_filename = str_replace('public://', '', $node_file->getFileUri());
-    $test_element = array(
-      'key' => 'enclosure',
-      'value' => "",
-      'attributes' => array(
-        'url' => file_create_url("public://$uploaded_filename", array('absolute' => TRUE)),
-        'length' => $node_file->getSize(),
-        'type' => $node_file->getMimeType()
-      ),
+    $test_element = sprintf(
+      '<enclosure url="%s" length="%s" type="%s" />',
+      file_create_url("public://$uploaded_filename", array('absolute' => TRUE)),
+      $node_file->getSize(),
+      $node_file->getMimeType()
     );
-    $this->assertRaw(format_xml_elements(array($test_element)), 'File field RSS enclosure is displayed when viewing the RSS feed.');
+    $this->assertRaw($test_element, 'File field RSS enclosure is displayed when viewing the RSS feed.');
   }
 }
diff --git a/core/modules/node/src/Tests/NodeRSSContentTest.php b/core/modules/node/src/Tests/NodeRSSContentTest.php
index e4b7cb3..6deb8af 100644
--- a/core/modules/node/src/Tests/NodeRSSContentTest.php
+++ b/core/modules/node/src/Tests/NodeRSSContentTest.php
@@ -54,12 +54,9 @@ function testNodeRSSContent() {
     $this->assertNoText($non_rss_content, 'Node content not designed for RSS does not appear in RSS feed.');
 
     // Check that extra RSS elements and namespaces are added to RSS feed.
-    $test_element = array(
-      'key' => 'testElement',
-      'value' => t('Value of testElement RSS element for node !nid.', array('!nid' => $node->id())),
-    );
+    $test_element = '<testElement>' . t('Value of testElement RSS element for node !nid.', array('!nid' => $node->id())) . '</testElement>';
     $test_ns = 'xmlns:drupaltest="http://example.com/test-namespace"';
-    $this->assertRaw(format_xml_elements(array($test_element)), 'Extra RSS elements appear in RSS feed.');
+    $this->assertRaw($test_element, 'Extra RSS elements appear in RSS feed.');
     $this->assertRaw($test_ns, 'Extra namespaces appear in RSS feed.');
 
     // Check that content added in 'rss' view mode doesn't appear when
diff --git a/core/modules/taxonomy/src/Tests/RssTest.php b/core/modules/taxonomy/src/Tests/RssTest.php
index 7fa3f10..98890a0 100644
--- a/core/modules/taxonomy/src/Tests/RssTest.php
+++ b/core/modules/taxonomy/src/Tests/RssTest.php
@@ -97,14 +97,12 @@ function testTaxonomyRss() {
 
     // Check that the term is displayed when the RSS feed is viewed.
     $this->drupalGet('rss.xml');
-    $test_element = array(
-      'key' => 'category',
-      'value' => $term1->getName(),
-      'attributes' => array(
-        'domain' => $term1->url('canonical', array('absolute' => TRUE)),
-      ),
+    $test_element = sprintf(
+      '<category %s>%s</category>',
+      'domain="' . $term1->url('canonical', array('absolute' => TRUE)) . '"',
+      $term1->getName()
     );
-    $this->assertRaw(format_xml_elements(array($test_element)), 'Term is displayed when viewing the rss feed.');
+    $this->assertRaw($test_element, 'Term is displayed when viewing the rss feed.');
 
     // Test that the feed page exists for the term.
     $this->drupalGet("taxonomy/term/{$term1->id()}/feed");
@@ -121,12 +119,9 @@ function testTaxonomyRss() {
     $view->storage->save();
     // Check the article is shown in the feed.
     $node = $this->drupalGetNodeByTitle($edit['title[0][value]']);
-    $raw_xml = format_xml_elements([[
-      'key' => 'title',
-      'value' => $node->label(),
-    ]]);
+    $raw_xml = '<title>' . $node->label() . '</title>';
     $this->drupalGet('taxonomy/term/all/feed');
-    $this->assertRaw($raw_xml);
+    $this->assertRaw($raw_xml, "Raw text '$raw_xml' is found.");
     // Unpublish the article and check that it is not shown in the feed.
     $node->setPublished(FALSE)->save();
     $this->drupalGet('taxonomy/term/all/feed');
diff --git a/core/modules/views/src/Plugin/views/style/Rss.php b/core/modules/views/src/Plugin/views/style/Rss.php
index fbbf4dd..274c5be 100644
--- a/core/modules/views/src/Plugin/views/style/Rss.php
+++ b/core/modules/views/src/Plugin/views/style/Rss.php
@@ -83,7 +83,7 @@ public function buildOptionsForm(&$form, FormStateInterface $form_state) {
    * Return an array of additional XHTML elements to add to the channel.
    *
    * @return
-   *   An array that can be passed to format_xml_elements().
+   *   A render array.
    */
   protected function getChannelElements() {
     return array();
diff --git a/core/modules/views/views.theme.inc b/core/modules/views/views.theme.inc
index d512b1d..7a75027 100644
--- a/core/modules/views/views.theme.inc
+++ b/core/modules/views/views.theme.inc
@@ -895,7 +895,7 @@ function template_preprocess_views_view_rss(&$variables) {
   $variables['langcode'] = SafeMarkup::checkPlain(\Drupal::languageManager()->getCurrentLanguage()->getId());
   $variables['namespaces'] = new Attribute($style->namespaces);
   $variables['items'] = $items;
-  $variables['channel_elements'] = format_xml_elements($style->channel_elements);
+  $variables['channel_elements'] = \Drupal::service('renderer')->render($style->channel_elements);
 
   // During live preview we don't want to output the header since the contents
   // of the feed are being displayed inside a normal HTML page.