Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/lib/Drupal/Component/Utility/NestedArray.php

@@ -349,7 +349,7 @@ class NestedArray {
    *
    * @param array $array
    *   The filtered nested array.
-   * @param callable|NULL $callable
+   * @param callable|null $callable
    *   The callable to apply for filtering.
    *
    * @return array

core/lib/Drupal/Component/Utility/OpCodeCache.php

@@ -9,6 +9,16 @@ namespace Drupal\Component\Utility;
  */
 class OpCodeCache {
 
+  /**
+   * Checks if OpCodeCache is enabled.
+   *
+   * @return bool
+   *   TRUE if opcache is enabled, FALSE otherwise.
+   */
+  public static function isEnabled() {
+    return extension_loaded('Zend OPcache') && ini_get('opcache.enable');
+  }
+
   /**
    * Invalidates a PHP file from a possibly active opcode cache.
    *

core/lib/Drupal/Component/Utility/SortArray.php

@@ -81,9 +81,9 @@ class SortArray {
    * @return int
    *   The comparison result for uasort().
    */
-   public static function sortByTitleProperty($a, $b) {
-     return static::sortByKeyString($a, $b, '#title');
-   }
+  public static function sortByTitleProperty($a, $b) {
+    return static::sortByKeyString($a, $b, '#title');
+  }
 
   /**
    * Sorts a string array item by an arbitrary key.

core/lib/Drupal/Component/Utility/Xss.php

@@ -224,6 +224,8 @@ class Xss {
             $skip_protocol_filtering = substr($attribute_name, 0, 5) === 'data-' || in_array($attribute_name, array(
               'title',
               'alt',
+              'rel',
+              'property',
             ));
 
             $working = $mode = 1;

core/lib/Drupal/Component/Utility/composer.json

@@ -7,7 +7,7 @@
   "require": {
     "php": ">=5.5.9",
     "paragonie/random_compat": "~1.0",
-    "drupal/core-render": "~8.1"
+    "drupal/core-render": "~8.2"
   },
   "autoload": {
     "psr-4": {