diff --git a/convert.php b/convert.php
index 4853b90..9a02ddb 100644
--- a/convert.php
+++ b/convert.php
@@ -15,8 +15,8 @@ class convert
     * @param string $inputDate The date to modify
     * @param string $inputFormat The input format of the date
     * @param string $outputFormat The output format of the date
-    * @param bool|null $exception If set, generate an exception if the provided
-    * date is invalid
+    * @param boolean|null $exception If set, generate an exception if the
+    * provided date is invalid
     * @return string
     */
   public static function convertDate ($inputDate, $inputFormat, $outputFormat,