diff --git a/include/admin/PhorumInputForm.php b/include/admin/PhorumInputForm.php
index 9ad733293..3f17956b5 100644
--- a/include/admin/PhorumInputForm.php
+++ b/include/admin/PhorumInputForm.php
@@ -39,7 +39,7 @@ class PhorumInputForm {
     var $_submit;
     var $_help;
 
-    function PhorumInputForm ( $action = "", $method = "get", $submit = "Submit", $target = "", $enctype = "", $events = array() )
+    function __construct($action = "", $method = "get", $submit = "Submit", $target = "", $enctype = "", $events = array())
     {
         $this->_action = ( empty( $action ) ) ? $_SERVER["PHP_SELF"] : $action;
         $this->_method = $method;
@@ -208,7 +208,7 @@ function show()
     {
         global $PHORUM;
 
-        if(count($this->_help)){
+        if (is_array($this->_help) && count($this->_help)) {
             echo "<script type=\"text/javascript\">\nvar help = Array;\n";
             foreach($this->_help as $key=>$data){
                 echo "help[$key] = [\"$data[0]\", \"$data[1]\"];\n";
diff --git a/include/admin/badwords.php b/include/admin/badwords.php
index 1ded907a0..79d5c5017 100644
--- a/include/admin/badwords.php
+++ b/include/admin/badwords.php
@@ -154,7 +154,7 @@
 
     echo "<hr class=\"PhorumAdminHR\" />";
 
-    if(count($bad_words)){
+    if (is_array($bad_words) && count($bad_words)) {
 
         echo "<table border=\"0\" cellspacing=\"1\" cellpadding=\"0\" class=\"PhorumAdminTable\" width=\"100%\">\n";
         echo "<tr>\n";
diff --git a/include/admin/upgrade.php b/include/admin/upgrade.php
index 282eddde2..7dce4c346 100644
--- a/include/admin/upgrade.php
+++ b/include/admin/upgrade.php
@@ -27,6 +27,7 @@
 
 require_once './include/admin/PhorumInputForm.php';
 require_once './include/version_functions.php';
+require_once './include/misc/polyfill-each.php';
 
 $is_module_upgrade = isset($_POST['is_module_upgrade'])
       ? ($_POST['is_module_upgrade'] ? 1 : 0)
diff --git a/include/api/custom_field.php b/include/api/custom_field.php
index 0e09c8148..fc73d170f 100644
--- a/include/api/custom_field.php
+++ b/include/api/custom_field.php
@@ -382,7 +382,7 @@ function phorum_api_custom_field_restore($id)
  *     Returns the input array with the custom fields added.
  */
 function phorum_api_custom_field_apply(
-    $field_type = NULL, $data_array, $raw_data = FALSE)
+    $field_type, $data_array, $raw_data = FALSE)
 {
     global $PHORUM;
 
diff --git a/include/api/system.php b/include/api/system.php
index b0a89ed94..d619e2090 100644
--- a/include/api/system.php
+++ b/include/api/system.php
@@ -123,7 +123,7 @@ function phorum_api_system_get_max_upload()
 function phorum_api_system_phpsize2bytes($size)
 {
     $size = trim($size);
-    $last = strtolower($size{strlen($size)-1});
+    $last = strtolower($size[strlen($size)-1]);
     switch($last) {
        // The 'G' modifier is available since PHP 5.1.0
        case 'g':
diff --git a/include/db/PhorumDB.php b/include/db/PhorumDB.php
index 1e3c89dc2..0aa6ba9f9 100644
--- a/include/db/PhorumDB.php
+++ b/include/db/PhorumDB.php
@@ -55,6 +55,8 @@
 // included separately from the Phorum core code.)
 defined('PHORUM_PATH') or define('PHORUM_PATH', dirname(__FILE__).'/../..');
 
+require_once __DIR__.'/../misc/polyfill-each.php';
+
 // ----------------------------------------------------------------------
 // Definitions
 // ----------------------------------------------------------------------
diff --git a/include/misc/polyfill-each.php b/include/misc/polyfill-each.php
new file mode 100644
index 000000000..9e12bdea3
--- /dev/null
+++ b/include/misc/polyfill-each.php
@@ -0,0 +1,54 @@
+<?php
+// MIT License
+//
+// Copyright (c) 2021 Christiaan Bye
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// https://github.com/ChristiaanBye/polyfill-each
+
+if (!function_exists('each')) {
+    /**
+     * @param array $array Although the actual function accepted objects, it was discouraged to pass them. Hence for the
+     *                     shim only an array is supported.
+     *
+     * @return array|false
+     */
+    function each(array &$array)
+    {
+        $key   = key($array);
+        $value = current($array);
+
+        if ($key === null) {
+            // key() returns null if the array pointer is beyond the list of element or if the array is empty. If the
+            // same scenario occurred in the each() function, a false was returned instead. Hence returning false here
+            return false;
+        }
+
+        // Advance the array pointer before returning
+        next($array);
+
+        return array(
+            1       => $value,
+            'value' => $value,
+            0       => $key,
+            'key'   => $key
+        );
+    }
+}
diff --git a/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.full.php b/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.full.php
index d2f821bcb..da65889a7 100644
--- a/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.full.php
+++ b/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.full.php
@@ -164,7 +164,7 @@ class ConvertCharset {
 	 * @param boolean $TurnOnEntities
 	 * @access public
 	 */
-	function ConvertCharset ($FromCharset, $ToCharset, $TurnOnEntities = false)
+	function __construct($FromCharset, $ToCharset, $TurnOnEntities = false)
 	{
 		/**
 		 * For all people who like to use uppercase for charset encoding names :)
diff --git a/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.php b/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.php
index 98840b21a..605b7b2b4 100644
--- a/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.php
+++ b/mods/compat_iconv/convertcharset-1.1/ConvertCharset.class.php
@@ -4,6 +4,7 @@
 define ("CONVERT_TABLES_DIR", $PATH_TO_CLASS);
 define ("DEBUG_MODE", 1);
 
+require_once __DIR__.'/../../include/misc/polyfill-each.php';
 
 class ConvertCharset{
      var $RecognizedEncoding; // (boolean) This value keeps information if string contains multibyte chars.
diff --git a/mods/spamhurdles/api.php b/mods/spamhurdles/api.php
index 9e653d940..07aa90ad1 100644
--- a/mods/spamhurdles/api.php
+++ b/mods/spamhurdles/api.php
@@ -691,7 +691,7 @@ function spamhurdles_iScramble_escape($plain)
 
     for ($i = 0; $i < strlen($plain); $i++)
     {
-        $char = $plain{$i};
+        $char = $plain[$i];
         if (strpos($passChars, $char) === false)
         {
             // $char is not in the list of $passChars. Encode in hex format
@@ -753,7 +753,7 @@ function spamhurdles_iScramble($plain, $longPwd=False, $rot13=False, $sorry="<i>
         $availChars = substr("0123456789", 0, $numberOfColumns);
         for ($i = 0 ; $i < $numberOfColumns; $i++)
         {
-            $char = $availChars{ random_int(0, strlen($availChars)-1) };
+            $char = $availChars[random_int(0, strlen($availChars)-1)];
             $password .= $char;
             $availChars = str_replace($char, "", $availChars);
         }
@@ -768,7 +768,7 @@ function spamhurdles_iScramble($plain, $longPwd=False, $rot13=False, $sorry="<i>
     {
         for($j = 0; $j < $numberOfColumns; $j++ )
         {
-            $scrambled{(int)(((int)$scramblePassword{$k}) * $numberOfRows) + $i} = $escaped{$k};
+            $scrambled[(int)(((int)$scramblePassword[$k]) * $numberOfRows) + $i] = $escaped[$k];
             $k++;
         }
     }
diff --git a/mods/spamhurdles/captcha/class.banner.php b/mods/spamhurdles/captcha/class.banner.php
index bdf246bfd..731d0ece4 100644
--- a/mods/spamhurdles/captcha/class.banner.php
+++ b/mods/spamhurdles/captcha/class.banner.php
@@ -1,7 +1,7 @@
 <?php
 class banner
 {
-    function banner($font = "banner.fnt")
+    function __construct($font = "banner.fnt")
     {
         $font = basename($font);
 
diff --git a/mods/spamhurdles/captcha/class.captcha_base.php b/mods/spamhurdles/captcha/class.captcha_base.php
index 4b65db11d..63abad6ac 100644
--- a/mods/spamhurdles/captcha/class.captcha_base.php
+++ b/mods/spamhurdles/captcha/class.captcha_base.php
@@ -5,8 +5,8 @@
 
 // The default set of characters to create random strings with.
 define("CAPTCHA_RANDOMCHARS",
-    "0123456789" .
-    "abcdefghijklmnopqrstuvwxyz",
+    "0123456789".
+    "abcdefghijklmnopqrstuvwxyz".
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 );
 
diff --git a/mods/spamhurdles/include/crypt/aes.php b/mods/spamhurdles/include/crypt/aes.php
index 792ee5c27..869fa25c5 100644
--- a/mods/spamhurdles/include/crypt/aes.php
+++ b/mods/spamhurdles/include/crypt/aes.php
@@ -127,7 +127,7 @@ class Crypt_AES extends Crypt_Rijndael {
      * @return Crypt_AES
      * @access public
      */
-    function Crypt_AES($mode = CRYPT_AES_MODE_CBC)
+    function __construct($mode = CRYPT_AES_MODE_CBC)
     {
         if ( !defined('CRYPT_AES_MODE') ) {
             switch (true) {
@@ -166,7 +166,7 @@ function Crypt_AES($mode = CRYPT_AES_MODE_CBC)
         }
 
         if (CRYPT_AES_MODE == CRYPT_AES_MODE_INTERNAL) {
-            parent::Crypt_Rijndael($this->mode);
+            parent::__construct($this->mode);
         }
     }
 
diff --git a/mods/spamhurdles/include/crypt/rijndael.php b/mods/spamhurdles/include/crypt/rijndael.php
index 164116003..b37ed956c 100644
--- a/mods/spamhurdles/include/crypt/rijndael.php
+++ b/mods/spamhurdles/include/crypt/rijndael.php
@@ -358,7 +358,7 @@ class Crypt_Rijndael {
      * @return Crypt_Rijndael
      * @access public
      */
-    function Crypt_Rijndael($mode = CRYPT_MODE_RIJNDAEL_CBC)
+    function __construct($mode = CRYPT_MODE_RIJNDAEL_CBC)
     {
         switch ($mode) {
             case CRYPT_RIJNDAEL_MODE_ECB: