diff --git a/composer.json b/composer.json
index 72e5568..2a9f73c 100644
--- a/composer.json
+++ b/composer.json
@@ -11,8 +11,8 @@
         "php-curl-class/php-curl-class": "^4.6"
     },
     "require-dev": {
-        "mikey179/vfsstream": "1.5.*",
-        "phpunit/phpunit": "4.7.*",
+        "mikey179/vfsstream": "1.6.*",
+        "phpunit/phpunit": "4.8.*",
         "phpdocumentor/phpdocumentor": "~2.8"
     },
     "autoload": {
diff --git a/src/Document/Anchor.php b/src/Document/Anchor.php
index d30f3a5..62caf16 100644
--- a/src/Document/Anchor.php
+++ b/src/Document/Anchor.php
@@ -15,6 +15,7 @@ class Anchor extends Base {
   protected $targetAnchorPosition;
   protected $originAnchorPosition;
   protected $targetComponentIdentifier;
+  protected $target;
   protected $rangeStart;
   protected $rangeLength;
 
@@ -37,6 +38,7 @@ protected function optional() {
       'targetComponentIdentifier',
       'rangeStart',
       'rangeLength',
+      'target'
     ));
   }
 
@@ -102,6 +104,29 @@ public function setTargetComponentIdentifier($value) {
     return $this;
   }
 
+  /**
+   * Setter for target.
+   *
+   * @param mixed $value
+   *   A target ID.
+   *
+   * @return $this
+   */
+  public function setTarget($value) {
+    $this->target = (string) $value;
+    return $this;
+  }
+
+  /**
+   * Getter for the target.
+   *
+   * @return string
+   *   The Target identifier.
+   */
+  public function getTarget() {
+    return $this->target;
+  }
+
   /**
    * Getter for rangeStart.
    */
diff --git a/src/Document/Metadata.php b/src/Document/Metadata.php
index 44883da..ec7e4ed 100644
--- a/src/Document/Metadata.php
+++ b/src/Document/Metadata.php
@@ -335,7 +335,7 @@ public function setVideoURL($videoURL) {
    * Validates the keywords attribute.
    */
   protected function validateKeywords($value) {
-    if (count($this->keywords) > 49) {
+    if ($this->keywords !== NULL && count($this->keywords) > 49) {
       $this->triggerError('number of keywords limited to 50.');
       return FALSE;
     }