diff --git a/CHANGELOG.md b/CHANGELOG.md
index 222d589c..ffc18d0f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- You can now use `$smarty->setPHP7CompatMode()` to activate php7 compatibility mode when running PHP8
+
 ### Changed
 - Switch CI from Travis to Github CI
 - Updated unit tests to avoid skipped and risky test warnings
diff --git a/libs/Smarty.class.php b/libs/Smarty.class.php
index 06927b74..0257f365 100644
--- a/libs/Smarty.class.php
+++ b/libs/Smarty.class.php
@@ -640,6 +640,12 @@ class Smarty extends Smarty_Internal_TemplateBase
         'cache_dir'    => 'CacheDir',
     );
 
+    /**
+     * PHP7 Compatibility mode
+     * @var bool
+     */
+    private $php7CompatMode = false;
+
     /**
      * Initialize new Smarty object
      */
@@ -1369,4 +1375,23 @@ class Smarty extends Smarty_Internal_TemplateBase
         $isConfig ? $this->_joined_config_dir = join('#', $this->config_dir) :
             $this->_joined_template_dir = join('#', $this->template_dir);
     }
+
+    /**
+     * Activates PHP7 compatibility mode:
+     * - converts E_WARNINGS for "undefined array key" and "trying to read property of null" errors to E_NOTICE
+     *
+     * @void
+     */
+    public function setPHP7CompatMode(): void {
+        $this->php7CompatMode = true;
+    }
+
+    /**
+     * Indicates if PHP7 compatibility mode is set.
+     * @bool
+     */
+    public function getPHP7CompatMode(): bool {
+        return $this->php7CompatMode;
+    }
+
 }
diff --git a/libs/sysplugins/smarty_internal_errorhandler.php b/libs/sysplugins/smarty_internal_errorhandler.php
index 56dca18f..04f1c7f2 100644
--- a/libs/sysplugins/smarty_internal_errorhandler.php
+++ b/libs/sysplugins/smarty_internal_errorhandler.php
@@ -1,55 +1,54 @@
 <?php
 
 /**
- * Smarty error handler
+ * Smarty error handler to fix new error levels in PHP8 for backwards compatibility
  *
  * @package    Smarty
  * @subpackage PluginsInternal
- * @author     Uwe Tews
+ * @author     Simon Wisselink
  *
- * @deprecated
-Smarty does no longer use @filemtime()
  */
 class Smarty_Internal_ErrorHandler
 {
-    /**
-     * contains directories outside of SMARTY_DIR that are to be muted by muteExpectedErrors()
-     */
-    public static $mutedDirectories = array();
 
     /**
-     * error handler returned by set_error_handler() in self::muteExpectedErrors()
+     * Allows {$foo} where foo is unset.
+     * @var bool
      */
-    private static $previousErrorHandler = null;
+    public $allowUndefinedVars = true;
 
     /**
-     * Enable error handler to mute expected messages
-     *
+     * Allows {$foo.bar} where bar is unset and {$foo.bar1.bar2} where either bar1 or bar2 is unset.
+     * @var bool
      */
-    public static function muteExpectedErrors()
-    {
+    public $allowUndefinedArrayKeys = true;
+
+    private $previousErrorHandler = null;
+
+    /**
+     * Enable error handler to intercept errors
+     */
+    public function activate() {
         /*
-            error muting is done because some people implemented custom error_handlers using
+            Error muting is done because some people implemented custom error_handlers using
             http://php.net/set_error_handler and for some reason did not understand the following paragraph:
 
-                It is important to remember that the standard PHP error handler is completely bypassed for the
-                error types specified by error_types unless the callback function returns FALSE.
-                error_reporting() settings will have no effect and your error handler will be called regardless -
-                however you are still able to read the current value of error_reporting and act appropriately.
-                Of particular note is that this value will be 0 if the statement that caused the error was
-                prepended by the @ error-control operator.
-
-            Smarty deliberately uses @filemtime() over file_exists() and filemtime() in some places. Reasons include
-                - @filemtime() is almost twice as fast as using an additional file_exists()
-                - between file_exists() and filemtime() a possible race condition is opened,
-                  which does not exist using the simple @filemtime() approach.
+            It is important to remember that the standard PHP error handler is completely bypassed for the
+            error types specified by error_types unless the callback function returns FALSE.
+            error_reporting() settings will have no effect and your error handler will be called regardless -
+            however you are still able to read the current value of error_reporting and act appropriately.
+            Of particular note is that this value will be 0 if the statement that caused the error was
+            prepended by the @ error-control operator.
         */
-        $error_handler = array('Smarty_Internal_ErrorHandler', 'mutingErrorHandler');
-        $previous = set_error_handler($error_handler);
-        // avoid dead loops
-        if ($previous !== $error_handler) {
-            self::$previousErrorHandler = $previous;
-        }
+        $this->previousErrorHandler = set_error_handler([$this, 'handleError']);
+    }
+
+    /**
+     * Disable error handler
+     */
+    public function deactivate() {
+        restore_error_handler();
+        $this->previousErrorHandler = null;
     }
 
     /**
@@ -65,49 +64,21 @@ class Smarty_Internal_ErrorHandler
      *
      * @return bool
      */
-    public static function mutingErrorHandler($errno, $errstr, $errfile, $errline, $errcontext = array())
+    public function handleError($errno, $errstr, $errfile, $errline, $errcontext = [])
     {
-        $_is_muted_directory = false;
-        // add the SMARTY_DIR to the list of muted directories
-        if (!isset(self::$mutedDirectories[ SMARTY_DIR ])) {
-            $smarty_dir = realpath(SMARTY_DIR);
-            if ($smarty_dir !== false) {
-                self::$mutedDirectories[ SMARTY_DIR ] =
-                    array('file' => $smarty_dir, 'length' => strlen($smarty_dir),);
-            }
+        if ($this->allowUndefinedVars && $errstr == 'Attempt to read property "value" on null') {
+            return; // suppresses this error
         }
-        // walk the muted directories and test against $errfile
-        foreach (self::$mutedDirectories as $key => &$dir) {
-            if (!$dir) {
-                // resolve directory and length for speedy comparisons
-                $file = realpath($key);
-                if ($file === false) {
-                    // this directory does not exist, remove and skip it
-                    unset(self::$mutedDirectories[ $key ]);
-                    continue;
-                }
-                $dir = array('file' => $file, 'length' => strlen($file),);
-            }
-            if (!strncmp($errfile, $dir[ 'file' ], $dir[ 'length' ])) {
-                $_is_muted_directory = true;
-                break;
-            }
-        }
-        // pass to next error handler if this error did not occur inside SMARTY_DIR
-        // or the error was within smarty but masked to be ignored
-        if (!$_is_muted_directory || ($errno && $errno & error_reporting())) {
-            if (self::$previousErrorHandler) {
-                return call_user_func(
-                    self::$previousErrorHandler,
-                    $errno,
-                    $errstr,
-                    $errfile,
-                    $errline,
-                    $errcontext
-                );
-            } else {
-                return false;
-            }
+
+        if ($this->allowUndefinedArrayKeys && preg_match(
+            '/^(Undefined array key|Trying to access array offset on value of type null)/',
+            $errstr
+        )) {
+            return; // suppresses this error
         }
+
+        // pass all other errors through to the previous error handler or to the default PHP error handler
+        return $this->previousErrorHandler ?
+            call_user_func($this->previousErrorHandler, $errno, $errstr, $errfile, $errline, $errcontext) : false;
     }
 }
diff --git a/libs/sysplugins/smarty_internal_templatebase.php b/libs/sysplugins/smarty_internal_templatebase.php
index 200c11bb..b8d444e3 100644
--- a/libs/sysplugins/smarty_internal_templatebase.php
+++ b/libs/sysplugins/smarty_internal_templatebase.php
@@ -199,6 +199,12 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
         try {
             $_smarty_old_error_level =
                 isset($smarty->error_reporting) ? error_reporting($smarty->error_reporting) : null;
+
+            if ($smarty->getPHP7CompatMode()) {
+	            $errorHandler = new Smarty_Internal_ErrorHandler();
+	            $errorHandler->activate();
+            }
+
             if ($this->_objType === 2) {
                 /* @var Smarty_Internal_Template $this */
                 $template->tplFunctions = $this->tplFunctions;
@@ -242,6 +248,11 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
                     }
                 }
             }
+
+            if (isset($errorHandler)) {
+	            $errorHandler->deactivate();
+            }
+
             if (isset($_smarty_old_error_level)) {
                 error_reporting($_smarty_old_error_level);
             }
@@ -250,9 +261,13 @@ abstract class Smarty_Internal_TemplateBase extends Smarty_Internal_Data
             while (ob_get_level() > $level) {
                 ob_end_clean();
             }
-            if (isset($_smarty_old_error_level)) {
-                error_reporting($_smarty_old_error_level);
-            }
+	        if (isset($errorHandler)) {
+		        $errorHandler->deactivate();
+	        }
+
+	        if (isset($_smarty_old_error_level)) {
+		        error_reporting($_smarty_old_error_level);
+	        }
             throw $e;
         }
     }
diff --git a/tests/UnitTests/A_2/UndefinedTemplateVar/UndefinedTemplateVarTest.php b/tests/UnitTests/A_2/UndefinedTemplateVar/UndefinedTemplateVarTest.php
index b7aaf43c..090fcb47 100644
--- a/tests/UnitTests/A_2/UndefinedTemplateVar/UndefinedTemplateVarTest.php
+++ b/tests/UnitTests/A_2/UndefinedTemplateVar/UndefinedTemplateVarTest.php
@@ -16,7 +16,6 @@ class UndefinedTemplateVarTest extends PHPUnit_Smarty
     public function setUp(): void
     {
         $this->setUpSmarty(dirname(__FILE__));
-        error_reporting(E_ALL | E_STRICT);
     }
 
     public function testInit()
@@ -48,9 +47,9 @@ class UndefinedTemplateVarTest extends PHPUnit_Smarty
         $this->assertEquals($e1, $e2);
     }
 
-	/**
-	 * Test Error suppression template object fetched by Smarty object
-	 */
+    /**
+     * Test Error suppression template object fetched by Smarty object
+     */
     public function testErrorDisabledTplObject_2()
     {
         $e1 = error_reporting();
@@ -66,27 +65,73 @@ class UndefinedTemplateVarTest extends PHPUnit_Smarty
      */
     public function testError()
     {
-	    $exceptionThrown = false;
+        $exceptionThrown = false;
 
         try {
-	        $e1 = error_reporting();
-	        $this->assertEquals('undefined = ', $this->smarty->fetch('001_main.tpl'));
-	        $e2 = error_reporting();
-	        $this->assertEquals($e1, $e2);
+            $e1 = error_reporting();
+            $this->assertEquals('undefined = ', $this->smarty->fetch('001_main.tpl'));
+            $e2 = error_reporting();
+            $this->assertEquals($e1, $e2);
         } catch (Exception $e) {
 
-        	$exceptionThrown = true;
-	        $this->assertStringStartsWith('Undefined ', $e->getMessage());
-	        $this->assertTrue(in_array(
-	        	get_class($e),
-		        array(
-		        	'PHPUnit_Framework_Error_Warning',
-			        'PHPUnit_Framework_Error_Notice',
-			        'PHPUnit\Framework\Error\Warning',
-			        'PHPUnit\Framework\Error\Notice',
-		        )
-	        ));
+            $exceptionThrown = true;
+            $this->assertStringStartsWith('Undefined ', $e->getMessage());
+            $this->assertTrue(in_array(
+                get_class($e),
+                [
+                    'PHPUnit\Framework\Error\Warning',
+                    'PHPUnit\Framework\Error\Notice',
+                ]
+            ));
         }
-	    $this->assertTrue($exceptionThrown);
+        $this->assertTrue($exceptionThrown);
     }
+
+    public function testUndefinedSimpleVar() {
+        $this->smarty->setErrorReporting(E_ALL & ~E_NOTICE);
+        $this->smarty->setPHP7CompatMode();
+        $tpl = $this->smarty->createTemplate('string:a{if $undef}def{/if}b');
+        $this->assertEquals("ab", $this->smarty->fetch($tpl));
+    }
+
+    public function testUndefinedArrayIndex() {
+        $this->smarty->setErrorReporting(E_ALL & ~E_NOTICE);
+        $this->smarty->setPHP7CompatMode();
+        $tpl = $this->smarty->createTemplate('string:a{if $ar.undef}def{/if}b');
+        $tpl->assign('ar', []);
+        $this->assertEquals("ab", $this->smarty->fetch($tpl));
+    }
+
+    public function testUndefinedArrayIndexDeep() {
+        $this->smarty->setErrorReporting(E_ALL & ~E_NOTICE);
+        $this->smarty->setPHP7CompatMode();
+        $tpl = $this->smarty->createTemplate('string:a{if $ar.undef.nope.neither}def{/if}b');
+        $tpl->assign('ar', []);
+        $this->assertEquals("ab", $this->smarty->fetch($tpl));
+    }
+
+    public function testUndefinedArrayIndexError()
+    {
+        $exceptionThrown = false;
+
+        try {
+            $tpl = $this->smarty->createTemplate('string:a{if $ar.undef}def{/if}b');
+            $tpl->assign('ar', []);
+            $this->smarty->fetch($tpl);
+        } catch (Exception $e) {
+
+            $exceptionThrown = true;
+            $this->assertStringStartsWith('Undefined ', $e->getMessage());
+            $this->assertTrue(in_array(
+                get_class($e),
+                [
+                    'PHPUnit\Framework\Error\Warning',
+                    'PHPUnit\Framework\Error\Notice',
+                ]
+            ));
+        }
+        $this->assertTrue($exceptionThrown);
+    }
+
+
 }
diff --git a/tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionHtmlCheckboxesTest.php b/tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionHtmlCheckboxesTest.php
index 5ea998fd..ee277d5f 100644
--- a/tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionHtmlCheckboxesTest.php
+++ b/tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionHtmlCheckboxesTest.php
@@ -285,12 +285,7 @@ class PluginFunctionHtmlCheckboxesTest extends PHPUnit_Smarty
         $this->_errors = array();
         set_error_handler(array($this, 'error_handler'));
 
-        $n = "\n";
-        $expected = '<label><input type="checkbox" name="id[]" value="1000" />Joe Schmoe</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1001" checked="checked" />Jack Smith</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1002" />Jane Johnson</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1003" />Charlie Brown</label><br />';
-
+	    $this->smarty->setPHP7CompatMode();
         $tpl = $this->smarty->createTemplate('eval:{html_checkboxes name="id" options=$cust_radios selected=$customer_id separator="<br />"}');
         $tpl->assign('customer_id', new _object_noString(1001));
         $tpl->assign('cust_radios', array(
@@ -312,12 +307,6 @@ class PluginFunctionHtmlCheckboxesTest extends PHPUnit_Smarty
         $this->_errors = array();
         set_error_handler(array($this, 'error_handler'));
 
-        $n = "\n";
-        $expected = '<label><input type="checkbox" name="id[]" value="1000" />Joe Schmoe</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1001" checked="checked" />Jack Smith</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1002" />Jane Johnson</label><br />'
-            . $n . '<label><input type="checkbox" name="id[]" value="1003" />Charlie Brown</label><br />';
-
         $tpl = $this->smarty->createTemplate('eval:{html_checkboxes name="id" options=$cust_radios selected=$customer_id separator="<br />"}');
         $tpl->assign('customer_id', 1001);
         $tpl->assign('cust_radios', array(