diff --git a/helpers/PrerequisiteChecker.php b/helpers/PrerequisiteChecker.php
index a7c72260..1d83bbd3 100644
--- a/helpers/PrerequisiteChecker.php
+++ b/helpers/PrerequisiteChecker.php
@@ -4,7 +4,7 @@ class ERequirementNotMet extends Exception
 {
 }
 
-const REQUIRED_PHP_EXTENSIONS = ['fileinfo', 'pdo_sqlite', 'gd'];
+const REQUIRED_PHP_EXTENSIONS = ['fileinfo', 'pdo_sqlite', 'gd', 'ctype']];
 const REQUIRED_SQLITE_VERSION = '3.8.3';
 
 class PrerequisiteChecker