diff --git a/src/Plugin/search_api/processor/Tokenizer.php b/src/Plugin/search_api/processor/Tokenizer.php
index 3b6c0b61..f682c9b9 100644
--- a/src/Plugin/search_api/processor/Tokenizer.php
+++ b/src/Plugin/search_api/processor/Tokenizer.php
@@ -59,7 +59,7 @@ public function buildConfigurationForm(array $form, FormStateInterface $form_sta
     $form = parent::buildConfigurationForm($form, $form_state);
 
     $args = [
-      ':pcre-url' => Url::fromUri('http://www.php.net/manual/regexp.reference.character-classes.php')->toString(),
+      ':pcre-url' => Url::fromUri('https://php.net/manual/regexp.reference.character-classes.php')->toString(),
       ':doc-url' => Url::fromUri('https://api.drupal.org/api/drupal/core!lib!Drupal!Component!Utility!Unicode.php/constant/Unicode%3A%3APREG_CLASS_WORD_BOUNDARY/8')->toString(),
     ];
     $form['spaces'] = [