diff --git a/core/modules/update/templates/update-last-check.html.twig b/core/modules/update/templates/update-last-check.html.twig
new file mode 100644
index 0000000..86ed1ff
--- /dev/null
+++ b/core/modules/update/templates/update-last-check.html.twig
@@ -0,0 +1,22 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the last time we checked for update data.
+ *
+ * Available variables:
+ * - last: The timestamp when the site last checked for available updates.
+ *
+ * @see template_preprocess()
+ * @see template_preprocess_update_last_check()
+ *
+ * @ingroup themeable
+ */
+#}
+<div class="update checked">
+  {% if last_checked %}
+    {{ 'Last checked: @time ago'|t({'@time': time}) }}
+  {% else %}
+    {{ 'Last checked: never'|t }}
+  {% endif %}
+  <span class="check-manually">({{ link }})</span>
+</div>
diff --git a/core/modules/update/templates/update-report.html.twig b/core/modules/update/templates/update-report.html.twig
new file mode 100644
index 0000000..90e1c80
--- /dev/null
+++ b/core/modules/update/templates/update-report.html.twig
@@ -0,0 +1,14 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the project status report.
+ *
+ * Available variables:
+ *   - data: An array of data about each project's status.
+ *
+ * @see template_preprocess()
+ * @see template_preprocess_update_report()
+ *
+ * @ingroup themeable
+ */
+#}
diff --git a/core/modules/update/templates/update-status-label.html.twig b/core/modules/update/templates/update-status-label.html.twig
new file mode 100644
index 0000000..2f036b1
--- /dev/null
+++ b/core/modules/update/templates/update-status-label.html.twig
@@ -0,0 +1,20 @@
+{#
+/**
+ * @file
+ * Default theme implementation for an update status label.
+ *
+ * Available variables:
+ * - text: The status label text.
+ * - attributes: Remaining HTML attributes for the element.
+ * - attributes.class: HTML classes that can be used to style contextually
+ *    through CSS.
+ *
+ * @see template_preprocess()
+ * @see template_preprocess_update_status_label()
+ *
+ * @ingroup themeable
+ */
+#}
+{% if text %}
+  <span{{ attributes }}>{{ text|t }}</span>
+{% endif %}
diff --git a/core/modules/update/templates/update-version.html.twig b/core/modules/update/templates/update-version.html.twig
new file mode 100644
index 0000000..f3aec6a
--- /dev/null
+++ b/core/modules/update/templates/update-version.html.twig
@@ -0,0 +1,32 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the version display of a project.
+ *
+ * Available variables:
+ *   - version: An array of data about the latest released version, containing:
+ *     - version: The version number.
+ *     - release_link: The URL for the release notes.
+ *     - date: The date of the release.
+ *     - download_link: The URL for the downloadable file.
+ *   - tag: The title of the project.
+ *   - class: A string containing extra classes for the wrapping table.
+ *
+ * @see template_preprocess
+ * @see template_preprocess_update_version
+ *
+ * @ingroup themeable
+ */
+#}
+<table{{ attributes }}>
+  <tr>
+    <td class="version-title">{{ tag }}</td>
+    <td class="version-details">
+      {{ version_link }}
+      <span class="version-date">{{ version_date }}</span>
+    </td>
+    <td class="version-links">
+      {{ version_links }}
+    </td>
+  </tr>
+</table>
diff --git a/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
index 0047a52..a6ce460 100644
--- a/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -67,7 +67,11 @@ function update_manager_update_form($form, $form_state = array(), $context) {
     return $form;
   }
 
-  $form['#theme'] = 'update_manager_update_form';
+  $last = state()->get('update.last_check') ?: 0;
+  $form['update_lask_check'] = array(
+    '#theme' => 'update_last_check',
+    '#last' => $last,
+  );
 
   $available = update_get_available(TRUE);
   if (empty($available)) {
@@ -268,23 +272,6 @@ function update_manager_update_form($form, $form_state = array(), $context) {
 }
 
 /**
- * Returns HTML for the first page in the process of updating projects.
- *
- * @param $variables
- *   An associative array containing:
- *   - form: A render element representing the form.
- *
- * @ingroup themeable
- */
-function theme_update_manager_update_form($variables) {
-  $form = $variables['form'];
-  $last = state()->get('update.last_check') ?: 0;
-  $output = theme('update_last_check', array('last' => $last));
-  $output .= drupal_render_children($form);
-  return $output;
-}
-
-/**
  * Form validation handler for update_manager_update_form().
  *
  * Ensures that at least one project is selected.
diff --git a/core/modules/update/update.module b/core/modules/update/update.module
index 7dee311..e9b8663 100644
--- a/core/modules/update/update.module
+++ b/core/modules/update/update.module
@@ -257,21 +257,23 @@ function update_manager_access() {
  */
 function update_theme() {
   return array(
-    'update_manager_update_form' => array(
-      'render element' => 'form',
-      'file' => 'update.manager.inc',
-    ),
     'update_last_check' => array(
       'variables' => array('last' => NULL),
+      'template'  => 'update-last-check',
     ),
     'update_report' => array(
       'variables' => array('data' => NULL),
+      // 'template'  => 'update-report',
     ),
     'update_version' => array(
-      'variables' => array('version' => NULL, 'tag' => NULL, 'class' => array()),
+      'variables' => array('version' => NULL, 'tag' => NULL),
+      'file' => 'update.report.inc',
+      'template' => 'update-version',
     ),
     'update_status_label' => array(
       'variables' => array('status' => NULL),
+      'file' => 'update.report.inc',
+      'template' => 'update-status-label',
     ),
   );
 }
@@ -625,13 +627,11 @@ function _update_project_status_sort($a, $b) {
  * @see theme_update_available_updates_form()
  * @ingroup themeable
  */
-function theme_update_last_check($variables) {
+function template_preprocess_update_last_check(&$variables) {
   $last = $variables['last'];
-  $output = '<div class="update checked">';
-  $output .= $last ? t('Last checked: @time ago', array('@time' => format_interval(REQUEST_TIME - $last))) : t('Last checked: never');
-  $output .= ' <span class="check-manually">(' . l(t('Check manually'), 'admin/reports/updates/check', array('query' => drupal_get_destination())) . ')</span>';
-  $output .= "</div>\n";
-  return $output;
+  $variables['last_checked'] = ($last != NULL);
+  $variables['time'] = format_interval(REQUEST_TIME - $last);
+  $variables['link'] = l(t('Check manually'), 'admin/reports/updates/check', array('query' => drupal_get_destination()));
 }
 
 /**
diff --git a/core/modules/update/update.report.inc b/core/modules/update/update.report.inc
index 607b523..6bbd9cd 100644
--- a/core/modules/update/update.report.inc
+++ b/core/modules/update/update.report.inc
@@ -1,5 +1,7 @@
 <?php
 
+use Drupal\Core\Template\Attribute;
+
 /**
  * @file
  * Code required only when rendering the available updates report.
@@ -11,36 +13,51 @@
  * @see update_menu()
  */
 function update_status() {
+  $build = array();
+  $last = state()->get('update.last_check') ?: 0;
+  $build['last_check'] = array(
+    '#theme' => 'update_last_check',
+    '#last' => $last,
+  );
   if ($available = update_get_available(TRUE)) {
     module_load_include('inc', 'update', 'update.compare');
     $data = update_calculate_project_data($available);
-    return theme('update_report', array('data' => $data));
   }
   else {
-    return theme('update_report', array('data' => _update_no_data()));
+    $data = _update_no_data();
+  }
+
+  if (!is_array($data)) {
+    $build['data'] = array(
+      '#markup' => $data,
+      '#prefix' => '<p>',
+      '#suffix' => '</p>',
+    );
+    return $build;
   }
+
+
+  $build['report'] = array(
+    '#theme' => 'update_report',
+    '#data' => $data,
+  );
+  return $build;
 }
 
 /**
- * Returns HTML for the project status report.
+ * Prepares variables the project status report.
+ *
+ * Default template: container.html.twig.
  *
  * @param array $variables
  *   An associative array containing:
  *   - data: An array of data about each project's status.
  *
- * @ingroup themeable
  */
 function theme_update_report($variables) {
   $data = $variables['data'];
 
-  $last = state()->get('update.last_check') ?: 0;
-  $output = theme('update_last_check', array('last' => $last));
-
-  if (!is_array($data)) {
-    $output .= '<p>' . $data . '</p>';
-    return $output;
-  }
-
+  $output = '';
   $header = array();
   $rows = array();
 
@@ -134,32 +151,52 @@ function theme_update_report($variables) {
               ) {
             $version_class[] = 'version-recommended-strong';
           }
-          $versions_inner .= theme('update_version', array('version' => $project['releases'][$project['recommended']], 'tag' => t('Recommended version:'), 'class' => $version_class));
+          $versions_inner .= theme('update_version', array(
+            'version' => $project['releases'][$project['recommended']],
+            'tag' => t('Recommended version:'),
+            'attributes' => array('class' => $version_class),
+          ));
         }
 
         // Now, print any security updates.
         if (!empty($project['security updates'])) {
           $security_class[] = 'version-security';
           foreach ($project['security updates'] as $security_update) {
-            $versions_inner .= theme('update_version', array('version' => $security_update, 'tag' => t('Security update:'), 'class' => $security_class));
+            $versions_inner .= theme('update_version', array(
+              'version' => $security_update,
+              'tag' => t('Security update:'),
+              'attributes' => array('class' => $security_class),
+            ));
           }
         }
       }
 
       if ($project['recommended'] !== $project['latest_version']) {
-        $versions_inner .= theme('update_version', array('version' => $project['releases'][$project['latest_version']], 'tag' => t('Latest version:'), 'class' => array('version-latest')));
+        $versions_inner .= theme('update_version', array(
+          'version' => $project['releases'][$project['latest_version']],
+          'tag' => t('Latest version:'),
+          'attributes' => array('class' => array('version-latest')),
+        ));
       }
       if ($project['install_type'] == 'dev'
           && $project['status'] != UPDATE_CURRENT
           && isset($project['dev_version'])
           && $project['recommended'] !== $project['dev_version']) {
-        $versions_inner .= theme('update_version', array('version' => $project['releases'][$project['dev_version']], 'tag' => t('Development version:'), 'class' => array('version-latest')));
+        $versions_inner .= theme('update_version', array(
+          'version' => $project['releases'][$project['dev_version']],
+          'tag' => t('Development version:'),
+          'attributes' => array('class' => array('version-latest')),
+        ));
       }
     }
 
     if (isset($project['also'])) {
       foreach ($project['also'] as $also) {
-        $versions_inner .= theme('update_version', array('version' => $project['releases'][$also], 'tag' => t('Also available:'), 'class' => array('version-also-available')));
+        $versions_inner .= theme('update_version', array(
+          'version' => $project['releases'][$also],
+          'tag' => t('Also available:'),
+          'attributes' => array('class' => array('version-also-available')),
+        ));
       }
     }
 
@@ -261,28 +298,36 @@ function theme_update_report($variables) {
  * @see update_calculate_project_data()
  * @ingroup themeable
  */
-function theme_update_status_label($variables) {
+function template_preprocess_update_status_label(&$variables) {
+  $variables['attributes'] = new Attribute(array('class' => array()));
   switch ($variables['status']) {
     case UPDATE_NOT_SECURE:
-      return '<span class="security-error">' . t('Security update required!') . '</span>';
-
+      $variables['attributes']['class'] = 'security-error';
+      $variables['text'] = 'Security update required!';
+      break;
     case UPDATE_REVOKED:
-      return '<span class="revoked">' . t('Revoked!') . '</span>';
-
+      $variables['attributes']['class'] = 'revoked';
+      $variables['text'] = 'Revoked!';
+      break;
     case UPDATE_NOT_SUPPORTED:
-      return '<span class="not-supported">' . t('Not supported!') . '</span>';
-
+      $variables['attributes']['class'] = 'not-supported';
+      $variables['text'] = 'Not supported!';
+      break;
     case UPDATE_NOT_CURRENT:
-      return '<span class="not-current">' . t('Update available') . '</span>';
-
+      $variables['attributes']['class'] = 'not-current';
+      $variables['text'] = 'Update available';
+      break;
     case UPDATE_CURRENT:
-      return '<span class="current">' . t('Up to date') . '</span>';
-
+      $variables['attributes']['class'] = 'current';
+      $variables['text'] = 'Up to date';
+      break;
   }
 }
 
 /**
- * Returns HTML for the version display of a project.
+ * Prepare variables for the version display of a project.
+ *
+ * Default template: update-version.html.twig.
  *
  * @param array $variables
  *   An associative array containing:
@@ -292,36 +337,28 @@ function theme_update_status_label($variables) {
  *     - date: The date of the release.
  *     - download_link: The URL for the downloadable file.
  *   - tag: The title of the project.
- *   - class: A string containing extra classes for the wrapping table.
- *
- * @ingroup themeable
- */
-function theme_update_version($variables) {
+*/
+function template_preprocess_update_version(&$variables) {
   $version = $variables['version'];
-  $tag = $variables['tag'];
-  $class = implode(' ', $variables['class']);
+  // Add version to the classes.
+  $variables['attributes']['class'][] = 'version';
+  // Convert the attributes array to an Attribute object.
+  $variables['attributes'] = new Attribute($variables['attributes']);
+
+  $variables['version_link'] = l($version['version'], $version['release_link']);
+  $variables['version_date'] = format_date($version['date'], 'custom', 'Y-M-d');
 
-  $output = '';
-  $output .= '<table class="version ' . $class . '">';
-  $output .= '<tr>';
-  $output .= '<td class="version-title">' . $tag . "</td>\n";
-  $output .= '<td class="version-details">';
-  $output .= l($version['version'], $version['release_link']);
-  $output .= ' <span class="version-date">(' . format_date($version['date'], 'custom', 'Y-M-d') . ')</span>';
-  $output .= "</td>\n";
-  $output .= '<td class="version-links">';
   $links = array();
-  $links['update-download'] = array(
+  $links['download'] = array(
     'title' => t('Download'),
     'href' => $version['download_link'],
   );
-  $links['update-release-notes'] = array(
+  $links['release-notes'] = array(
     'title' => t('Release notes'),
     'href' => $version['release_link'],
   );
-  $output .= theme('links__update_version', array('links' => $links));
-  $output .= '</td>';
-  $output .= '</tr>';
-  $output .= "</table>\n";
-  return $output;
+  $variables['version_links'] = array(
+    '#theme' => 'links__update_version',
+    '#links' => $links,
+  );
 }