diff --git a/change_log.txt b/change_log.txt
index aa19638c..cb7a7347 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -1,6 +1,8 @@
 ===== 3.1.31-dev ===== (xx.xx.xx)
  14.08.2016
   - bugfix $smarty_>debugging = true; did E_NOTICE messages when {eval} tag was used https://github.com/smarty-php/smarty/issues/266
+  - bugfix Class 'Smarty_Internal_Runtime_ValidateCompiled' not found when upgrading from some older Smarty versions with existing
+           compiled or cached template files https://github.com/smarty-php/smarty/issues/269
 
 ===== 3.1.30 ===== (07.08.2016)
 
diff --git a/libs/Smarty.class.php b/libs/Smarty.class.php
index b6ba2685..7702e02e 100644
--- a/libs/Smarty.class.php
+++ b/libs/Smarty.class.php
@@ -121,7 +121,7 @@ class Smarty extends Smarty_Internal_TemplateBase
     /**
      * smarty version
      */
-    const SMARTY_VERSION = '3.1.31-dev/2';
+    const SMARTY_VERSION = '3.1.31-dev/3';
 
     /**
      * define variable scopes
diff --git a/libs/sysplugins/smarty_internal_extension_handler.php b/libs/sysplugins/smarty_internal_extension_handler.php
index edeb3958..bda8e82a 100644
--- a/libs/sysplugins/smarty_internal_extension_handler.php
+++ b/libs/sysplugins/smarty_internal_extension_handler.php
@@ -10,15 +10,20 @@
  * @subpackage PluginsInternal
  * @author     Uwe Tews
  *
- * @property Smarty_Internal_Runtime_TplFunction    $_tplFunction
- * @property Smarty_Internal_Runtime_Foreach        $_foreach
- * @property Smarty_Internal_Runtime_WriteFile      $_writeFile
+ * Runtime extensions
+ * @property Smarty_Internal_Runtime_CacheModify    $_cacheModify
+ * @property Smarty_Internal_Runtime_Capture        $_capture
  * @property Smarty_Internal_Runtime_CodeFrame      $_codeFrame
  * @property Smarty_Internal_Runtime_FilterHandler  $_filterHandler
+ * @property Smarty_Internal_Runtime_Foreach        $_foreach
  * @property Smarty_Internal_Runtime_GetIncludePath $_getIncludePath
- * @property Smarty_Internal_Runtime_UpdateScope    $_updateScope
- * @property Smarty_Internal_Runtime_CacheModify    $_cacheModify
+ * @property Smarty_Internal_Runtime_Make_Nocache   $_make_nocache
  * @property Smarty_Internal_Runtime_UpdateCache    $_updateCache
+ * @property Smarty_Internal_Runtime_UpdateScope    $_updateScope
+ * @property Smarty_Internal_Runtime_TplFunction    $_tplFunction
+ * @property Smarty_Internal_Runtime_WriteFile      $_writeFile
+ *
+ * Method extensions
  * @property Smarty_Internal_Method_GetTemplateVars $getTemplateVars
  * @property Smarty_Internal_Method_Append          $append
  * @property Smarty_Internal_Method_AppendByRef     $appendByRef
@@ -64,6 +69,7 @@ class Smarty_Internal_Extension_Handler
         if (!isset($smarty->ext->$name)) {
             $class = 'Smarty_Internal_Method_' . ucfirst($name);
             if (preg_match('/^(set|get)([A-Z].*)$/', $name, $match)) {
+                $pn = '';
                 if (!isset($this->_property_info[ $prop = $match[ 2 ] ])) {
                     // convert camel case to underscored name
                     $this->resolvedProperties[ $prop ] = $pn = strtolower(join('_',
@@ -127,6 +133,9 @@ class Smarty_Internal_Extension_Handler
         } else {
             $class = 'Smarty_Internal_Method_' . ucfirst($property_name);
         }
+        if (!class_exists($class)) {
+            return $this->$property_name = new Smarty_Internal_Undefined($class);
+        }
         return $this->$property_name = new $class();
     }
 
diff --git a/libs/sysplugins/smarty_internal_undefined.php b/libs/sysplugins/smarty_internal_undefined.php
index 23563e05..d6f4bf62 100644
--- a/libs/sysplugins/smarty_internal_undefined.php
+++ b/libs/sysplugins/smarty_internal_undefined.php
@@ -1,9 +1,9 @@
 <?php
 
 /**
- * Smarty Method AppendByRef
+ * Smarty Internal Undefined
  *
- * Smarty::appendByRef() method
+ * Class to handle undefined method calls or calls to obsolete runtime extensions
  *
  * @package    Smarty
  * @subpackage PluginsInternal
@@ -13,15 +13,30 @@ class Smarty_Internal_Undefined
 {
 
     /**
-     * This function is executed automatically when a compiled or cached template file is included
-     * - Decode saved properties from compiled template and cache files
-     * - Check if compiled or cache file is valid
+     * Name of undefined extension class
+     *
+     * @var string|null
+     */
+    public $class = null;
+
+    /**
+     * Smarty_Internal_Undefined constructor.
+     *
+     * @param null|string $class name of undefined extension class
+     */
+    public function __construct($class = null)
+    {
+        $this->class = $class;
+    }
+
+    /**
+     * Wrapper for obsolete class Smarty_Internal_Runtime_ValidateCompiled
      *
      * @param  \Smarty_Internal_Template $tpl
      * @param  array                     $properties special template properties
      * @param  bool                      $cache      flag if called from cache file
      *
-     * @return bool flag if compiled or cache file is valid
+     * @return bool false
      */
     public function decodeProperties(Smarty_Internal_Template $tpl, $properties, $cache = false)
     {
@@ -44,6 +59,10 @@ class Smarty_Internal_Undefined
      */
     public function __call($name, $args)
     {
-        throw new SmartyException(get_class($args[ 0 ]) . "->{$name}() undefined method");
+        if (isset($this->class)) {
+            throw new SmartyException("undefined extension class '{$this->class}'");
+        } else {
+            throw new SmartyException(get_class($args[ 0 ]) . "->{$name}() undefined method");
+        }
     }
 }
\ No newline at end of file