diff --git a/core/includes/unicode.inc b/core/includes/unicode.inc
index 8342ab2000f3ab1256f3038c3d37504ad23a0a5a..4dcdf570d2b9f07280b4efccf8c974c325f0e227 100644
--- a/core/includes/unicode.inc
+++ b/core/includes/unicode.inc
@@ -220,23 +220,6 @@ function drupal_strlen($text) {
   return Unicode::strlen($text);
 }
 
-/**
- * Lowercase a UTF-8 string.
- *
- * @param $text
- *   The string to run the operation on.
- *
- * @return string
- *   The string in lowercase.
- *
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.0.
- *   Use \Drupal\Component\Utility\Unicode::strtolower().
- * @ingroup php_wrappers
- */
-function drupal_strtolower($text) {
-  return Unicode::strtolower($text);
-}
-
 /**
  * Cuts off a piece of a string based on character indices and counts.
  *