diff --git a/ReadMe.md b/ReadMe.md
index 28cff12..ded4fce 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -23,3 +23,24 @@ Alternative setup composer local zip file repot:
 ## Install package
 
 `composer require egrajp/smarty-extended:^4.3`
+
+## How to update
+
+1) update the original composer for ^4.3
+2) copy over the src/sysplugins and all base files in src/
+3) check either function.html_checkboxes.php and function.html_options.php have changed
+4) copy src/plugins except the above two files, be sure to keep the block.t.php and function_popup*.php
+5) Create new release version as official relase number
+
+## Updated files (different from master)
+
+### New
+
+`src/plugins/block.t.php`
+`src/plugins/function_popup.php`
+`src/plugins/function_popup.init.php`
+
+### Changed
+
+`src/plugins/function.html_checkboxes.php`
+`src/plugins/function.html_options.php`
diff --git a/src/debug.tpl b/src/debug.tpl
index 4f82a58..cd93256 100644
--- a/src/debug.tpl
+++ b/src/debug.tpl
@@ -167,9 +167,7 @@
     </html>
 {/capture}
 <script type="text/javascript">
-    {$id = '__Smarty__'}
-    {if $display_mode}{$id = "$offset$template_name"|md5}{/if}
-    _smarty_console = window.open("", "console{$id}", "width=1024,height=600,left={$offset},top={$offset},resizable,scrollbars=yes");
+    _smarty_console = window.open("", "console{$targetWindow}", "width=1024,height=600,left={$offset},top={$offset},resizable,scrollbars=yes");
     _smarty_console.document.write("{$debug_output|escape:'javascript' nofilter}");
     _smarty_console.document.close();
 </script>
diff --git a/src/plugins/function.math.php b/src/plugins/function.math.php
index f9cf67f..34912d2 100644
--- a/src/plugins/function.math.php
+++ b/src/plugins/function.math.php
@@ -67,7 +67,7 @@ function smarty_function_math($params, $template)
     $equation = preg_replace('/\s+/', '', $equation);
 
     // Adapted from https://www.php.net/manual/en/function.eval.php#107377
-    $number = '(?:\d+(?:[,.]\d+)?|pi|π)'; // What is a number
+    $number = '-?(?:\d+(?:[,.]\d+)?|pi|π)'; // What is a number
     $functionsOrVars = '((?:0x[a-fA-F0-9]+)|([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*))';
     $operators = '[,+\/*\^%-]'; // Allowed math operators
     $regexp = '/^(('.$number.'|'.$functionsOrVars.'|('.$functionsOrVars.'\s*\((?1)*\)|\((?1)*\)))(?:'.$operators.'(?1))?)+$/';
diff --git a/src/plugins/modifier.escape.php b/src/plugins/modifier.escape.php
index 11e4468..e168679 100644
--- a/src/plugins/modifier.escape.php
+++ b/src/plugins/modifier.escape.php
@@ -115,7 +115,9 @@ function smarty_modifier_escape($string, $esc_type = 'html', $char_set = null, $
                     // see https://html.spec.whatwg.org/multipage/scripting.html#restrictions-for-contents-of-script-elements
                     '<!--' => '<\!--',
                     '<s'   => '<\s',
-                    '<S'   => '<\S'
+                    '<S'   => '<\S',
+	                "`" => "\\\\`",
+	                "\${" => "\\\\\\$\\{"
                 )
             );
         case 'mail':
diff --git a/src/plugins/modifier.truncate.php b/src/plugins/modifier.truncate.php
index 80dcdb5..d253e4a 100644
--- a/src/plugins/modifier.truncate.php
+++ b/src/plugins/modifier.truncate.php
@@ -26,7 +26,7 @@
  */
 function smarty_modifier_truncate($string, $length = 80, $etc = '...', $break_words = false, $middle = false)
 {
-    if ($length === 0) {
+    if ($length === 0 || $string === null) {
         return '';
     }
     if (Smarty::$_MBSTRING) {
diff --git a/src/plugins/modifiercompiler.count_characters.php b/src/plugins/modifiercompiler.count_characters.php
index b5d97e2..7798cab 100644
--- a/src/plugins/modifiercompiler.count_characters.php
+++ b/src/plugins/modifiercompiler.count_characters.php
@@ -25,8 +25,8 @@ function smarty_modifiercompiler_count_characters($params)
         return 'preg_match_all(\'/[^\s]/' . Smarty::$_UTF8_MODIFIER . '\',' . $params[ 0 ] . ', $tmp)';
     }
     if (Smarty::$_MBSTRING) {
-        return 'mb_strlen(' . $params[ 0 ] . ', \'' . addslashes(Smarty::$_CHARSET) . '\')';
+        return 'mb_strlen((string) ' . $params[ 0 ] . ', \'' . addslashes(Smarty::$_CHARSET) . '\')';
     }
     // no MBString fallback
-    return 'strlen(' . $params[ 0 ] . ')';
+    return 'strlen((string) ' . $params[ 0 ] . ')';
 }
diff --git a/src/plugins/modifiercompiler.count_words.php b/src/plugins/modifiercompiler.count_words.php
index cf2e502..48a3daa 100644
--- a/src/plugins/modifiercompiler.count_words.php
+++ b/src/plugins/modifiercompiler.count_words.php
@@ -27,5 +27,5 @@ function smarty_modifiercompiler_count_words($params)
                $params[ 0 ] . ', $tmp)';
     }
     // no MBString fallback
-    return 'str_word_count(' . $params[ 0 ] . ')';
+    return 'str_word_count((string) ' . $params[ 0 ] . ')';
 }
diff --git a/src/plugins/modifiercompiler.escape.php b/src/plugins/modifiercompiler.escape.php
index 602c3db..21b1b4c 100644
--- a/src/plugins/modifiercompiler.escape.php
+++ b/src/plugins/modifiercompiler.escape.php
@@ -64,7 +64,9 @@ function smarty_modifiercompiler_escape($params, Smarty_Internal_TemplateCompile
                 // see https://html.spec.whatwg.org/multipage/scripting.html#restrictions-for-contents-of-script-elements
                 return 'strtr((string)' .
                        $params[ 0 ] .
-                       ', array("\\\\" => "\\\\\\\\", "\'" => "\\\\\'", "\"" => "\\\\\"", "\\r" => "\\\\r", "\\n" => "\\\n", "</" => "<\/", "<!--" => "<\!--", "<s" => "<\s", "<S" => "<\S" ))';
+                       ', array("\\\\" => "\\\\\\\\", "\'" => "\\\\\'", "\"" => "\\\\\"", "\\r" => "\\\\r", 
+                       "\\n" => "\\\n", "</" => "<\/", "<!--" => "<\!--", "<s" => "<\s", "<S" => "<\S",
+                       "`" => "\\\\`", "\${" => "\\\\\\$\\{"))';
         }
     } catch (SmartyException $e) {
         // pass through to regular plugin fallback
diff --git a/src/plugins/modifiercompiler.lower.php b/src/plugins/modifiercompiler.lower.php
index ac9cc39..1f9cfb1 100644
--- a/src/plugins/modifiercompiler.lower.php
+++ b/src/plugins/modifiercompiler.lower.php
@@ -25,5 +25,5 @@ function smarty_modifiercompiler_lower($params)
         return 'mb_strtolower(' . $params[ 0 ] . ', \'' . addslashes(Smarty::$_CHARSET) . '\')';
     }
     // no MBString fallback
-    return 'strtolower(' . $params[ 0 ] . ')';
+    return 'strtolower((string) ' . $params[ 0 ] . ')';
 }
diff --git a/src/plugins/modifiercompiler.strip_tags.php b/src/plugins/modifiercompiler.strip_tags.php
index bd866a6..fd6cc72 100644
--- a/src/plugins/modifiercompiler.strip_tags.php
+++ b/src/plugins/modifiercompiler.strip_tags.php
@@ -21,7 +21,7 @@
 function smarty_modifiercompiler_strip_tags($params)
 {
     if (!isset($params[ 1 ]) || $params[ 1 ] === true || trim($params[ 1 ], '"') === 'true') {
-        return "preg_replace('!<[^>]*?>!', ' ', {$params[0]} ?: '')";
+        return "preg_replace('!<[^>]*?>!', ' ', (string) {$params[0]})";
     } else {
         return 'strip_tags((string) ' . $params[ 0 ] . ')';
     }
diff --git a/src/plugins/modifiercompiler.upper.php b/src/plugins/modifiercompiler.upper.php
index 31a90a0..9603051 100644
--- a/src/plugins/modifiercompiler.upper.php
+++ b/src/plugins/modifiercompiler.upper.php
@@ -21,8 +21,8 @@
 function smarty_modifiercompiler_upper($params)
 {
     if (Smarty::$_MBSTRING) {
-        return 'mb_strtoupper(' . $params[ 0 ] . ' ?? \'\', \'' . addslashes(Smarty::$_CHARSET) . '\')';
+        return 'mb_strtoupper((string) ' . $params[ 0 ] . ' ?? \'\', \'' . addslashes(Smarty::$_CHARSET) . '\')';
     }
     // no MBString fallback
-    return 'strtoupper(' . $params[ 0 ] . ' ?? \'\')';
+    return 'strtoupper((string) ' . $params[ 0 ] . ' ?? \'\')';
 }
diff --git a/src/plugins/outputfilter.trimwhitespace.php b/src/plugins/outputfilter.trimwhitespace.php
index 2f747ad..180cdd0 100644
--- a/src/plugins/outputfilter.trimwhitespace.php
+++ b/src/plugins/outputfilter.trimwhitespace.php
@@ -62,7 +62,7 @@ function smarty_outputfilter_trimwhitespace($source)
         }
     }
     $expressions = array(// replace multiple spaces between tags by a single space
-                         // can't remove them entirely, becaue that might break poorly implemented CSS display:inline-block elements
+                         // can't remove them entirely, because that might break poorly implemented CSS display:inline-block elements
                          '#(:SMARTY@!@|>)\s+(?=@!@SMARTY:|<)#s'                                    => '\1 \2',
                          // remove spaces between attributes (but not in attribute values!)
                          '#(([a-z0-9]\s*=\s*("[^"]*?")|(\'[^\']*?\'))|<[a-z0-9_]+)\s+([a-z/>])#is' => '\1 \5',
diff --git a/src/plugins/variablefilter.htmlspecialchars.php b/src/plugins/variablefilter.htmlspecialchars.php
index 3c85295..2eb12d2 100644
--- a/src/plugins/variablefilter.htmlspecialchars.php
+++ b/src/plugins/variablefilter.htmlspecialchars.php
@@ -15,5 +15,5 @@
  */
 function smarty_variablefilter_htmlspecialchars($source, Smarty_Internal_Template $template)
 {
-    return htmlspecialchars($source, ENT_QUOTES, Smarty::$_CHARSET);
+    return htmlspecialchars((string) $source, ENT_QUOTES, Smarty::$_CHARSET);
 }
diff --git a/src/sysplugins/smarty_internal_debug.php b/src/sysplugins/smarty_internal_debug.php
index 570819d..da67904 100644
--- a/src/sysplugins/smarty_internal_debug.php
+++ b/src/sysplugins/smarty_internal_debug.php
@@ -238,9 +238,12 @@ class Smarty_Internal_Debug extends Smarty_Internal_Data
         $_config_vars = $ptr->config_vars;
         ksort($_config_vars);
         $debugging = $smarty->debugging;
+        $templateName = $obj->source->type . ':' . $obj->source->name;
+        $displayMode = $debugging === 2 || !$full;
+        $offset = $this->offset * 50;
         $_template = new Smarty_Internal_Template($debObj->debug_tpl, $debObj);
         if ($obj->_isTplObj()) {
-            $_template->assign('template_name', $obj->source->type . ':' . $obj->source->name);
+            $_template->assign('template_name', $templateName);
         }
         if ($obj->_objType === 1 || $full) {
             $_template->assign('template_data', $this->template_data[ $this->index ]);
@@ -250,8 +253,8 @@ class Smarty_Internal_Debug extends Smarty_Internal_Data
         $_template->assign('assigned_vars', $_assigned_vars);
         $_template->assign('config_vars', $_config_vars);
         $_template->assign('execution_time', microtime(true) - $smarty->start_time);
-        $_template->assign('display_mode', $debugging === 2 || !$full);
-        $_template->assign('offset', $this->offset * 50);
+        $_template->assign('targetWindow', $displayMode ? md5("$offset$templateName") : '__Smarty__');
+        $_template->assign('offset', $offset);
         echo $_template->fetch();
         if (isset($full)) {
             $this->index--;
diff --git a/src/sysplugins/smarty_internal_errorhandler.php b/src/sysplugins/smarty_internal_errorhandler.php
index f57cc21..6f526c3 100644
--- a/src/sysplugins/smarty_internal_errorhandler.php
+++ b/src/sysplugins/smarty_internal_errorhandler.php
@@ -17,6 +17,12 @@ class Smarty_Internal_ErrorHandler
      */
     public $allowUndefinedVars = true;
 
+    /**
+     * Allows {$foo->propName} where propName is undefined.
+     * @var bool
+     */
+    public $allowUndefinedProperties = true;
+
     /**
      * Allows {$foo.bar} where bar is unset and {$foo.bar1.bar2} where either bar1 or bar2 is unset.
      * @var bool
@@ -80,6 +86,13 @@ class Smarty_Internal_ErrorHandler
             return; // suppresses this error
         }
 
+        if ($this->allowUndefinedProperties && preg_match(
+                '/^(Undefined property)/',
+                $errstr
+            )) {
+            return; // suppresses this error
+        }
+
         if ($this->allowUndefinedArrayKeys && preg_match(
             '/^(Undefined index|Undefined array key|Trying to access array offset on value of type)/',
             $errstr
diff --git a/src/sysplugins/smarty_template_compiled.php b/src/sysplugins/smarty_template_compiled.php
index 37d8f0a..b78a3b6 100644
--- a/src/sysplugins/smarty_template_compiled.php
+++ b/src/sysplugins/smarty_template_compiled.php
@@ -85,7 +85,7 @@ class Smarty_Template_Compiled extends Smarty_Template_Resource_Base
      *
      * @param Smarty_Internal_Template $_template
      *
-     * @return string
+     * @return void
      * @throws Exception
      */
     public function render(Smarty_Internal_Template $_template)