diff --git a/lib/Component.php b/lib/Component.php
index f33b628a..c1a63258 100644
--- a/lib/Component.php
+++ b/lib/Component.php
@@ -212,14 +212,14 @@ public function getComponents()
      * string ("HOME.EMAIL"). If you want to search on a specific property that
      * has not been assigned a group, specify ".EMAIL".
      *
-     * @param string $name
+     * @param string|null $name
      *
      * @return array
      */
     public function select($name)
     {
         $group = null;
-        $name = strtoupper($name);
+        $name = is_null($name) ? '' : strtoupper($name);
         if (false !== strpos($name, '.')) {
             list($group, $name) = explode('.', $name, 2);
         }
@@ -238,7 +238,7 @@ public function select($name)
                 return array_filter(
                     $result,
                     function ($child) use ($group) {
-                        return $child instanceof Property && strtoupper($child->group) === $group;
+                        return $child instanceof Property && strtoupper($child->group ?? '') === $group;
                     }
                 );
             }
@@ -249,7 +249,7 @@ function ($child) use ($group) {
         $result = [];
         foreach ($this->children as $childGroup) {
             foreach ($childGroup as $child) {
-                if ($child instanceof Property && strtoupper($child->group) === $group) {
+                if ($child instanceof Property && $child->group && strtoupper($child->group) === $group) {
                     $result[] = $child;
                 }
             }
diff --git a/lib/Parameter.php b/lib/Parameter.php
index 7e4d5574..5df6238e 100644
--- a/lib/Parameter.php
+++ b/lib/Parameter.php
@@ -47,12 +47,12 @@ class Parameter extends Node
      *
      * It's recommended to use the create:: factory method instead.
      *
-     * @param string $name
+     * @param string|null $name
      * @param string $value
      */
     public function __construct(Document $root, $name, $value = null)
     {
-        $this->name = strtoupper($name);
+        $this->name = is_null($name) ? '' : strtoupper($name);
         $this->root = $root;
         if (is_null($name)) {
             $this->noName = true;
diff --git a/lib/Property.php b/lib/Property.php
index 50cda968..56096daf 100644
--- a/lib/Property.php
+++ b/lib/Property.php
@@ -30,7 +30,7 @@ abstract class Property extends Node
      *
      * This is only used in vcards
      *
-     * @var string
+     * @var string|null
      */
     public $group;