diff --git a/src/Intervention/Image/AbstractDriver.php b/src/Intervention/Image/AbstractDriver.php
index d2356ae8..6c591a79 100644
--- a/src/Intervention/Image/AbstractDriver.php
+++ b/src/Intervention/Image/AbstractDriver.php
@@ -104,8 +104,12 @@ abstract class AbstractDriver
      */
     private function getCommandClassName($name)
     {
-        $name = mb_convert_case($name[0], MB_CASE_UPPER, 'utf-8') . mb_substr($name, 1, mb_strlen($name));
-        
+        if (extension_loaded('mbstring')) {
+            $name = mb_strtoupper(mb_substr($name, 0, 1)) . mb_substr($name, 1);
+        } else {
+            $name = strtoupper(substr($name, 0, 1)) . substr($name, 1);
+        }
+
         $drivername = $this->getDriverName();
         $classnameLocal = sprintf('\Intervention\Image\%s\Commands\%sCommand', $drivername, ucfirst($name));
         $classnameGlobal = sprintf('\Intervention\Image\Commands\%sCommand', ucfirst($name));