diff --git a/src/Valitron/Validator.php b/src/Valitron/Validator.php
index fad587b..b334f8e 100644
--- a/src/Valitron/Validator.php
+++ b/src/Valitron/Validator.php
@@ -1133,7 +1133,12 @@ class Validator
         $message = isset($msgs[$rule]) ? $msgs[$rule] : self::ERROR_DEFAULT;
 
         // Ensure message contains field label
-        if (mb_strpos($message, '{field}') === false) {
+		if (function_exists('mb_strpos')) {
+			$notContains = mb_strpos($message, '{field}') === false;
+		} else {
+			$notContains = strpos($message, '{field}') === false;
+		}
+		if ($notContains) {
             $message = '{field} ' . $message;
         }