diff --git a/library/attach_mod/displaying.php b/library/attach_mod/displaying.php
index 0a010d9f6..6d2b91f44 100644
--- a/library/attach_mod/displaying.php
+++ b/library/attach_mod/displaying.php
@@ -83,7 +83,7 @@ function init_display_template($template_var, $replacement, $filename = 'viewtop
     }
 
     $complete_filename = $filename;
-    if (substr($complete_filename, 0, 1) != '/') {
+    if ($complete_filename[0] != '/') {
         $complete_filename = $template->root . '/' . $complete_filename;
     }
 
diff --git a/library/attach_mod/includes/functions_attach.php b/library/attach_mod/includes/functions_attach.php
index 6898bcf27..891780b9a 100644
--- a/library/attach_mod/includes/functions_attach.php
+++ b/library/attach_mod/includes/functions_attach.php
@@ -83,7 +83,7 @@ function base64_unpack($string)
 
     for ($i = 1; $i <= $length; $i++) {
         $pos = $length - $i;
-        $operand = strpos($chars, substr($string, $pos, 1));
+        $operand = strpos($chars, $string[$pos]);
         $exponent = $base ** ($i - 1);
         $decValue = $operand * $exponent;
         $number += $decValue;
@@ -131,7 +131,7 @@ function auth_unpack($auth_cache)
     $auth_len = 1;
 
     for ($pos = 0; $pos < strlen($auth_cache); $pos += $auth_len) {
-        $forum_auth = substr($auth_cache, $pos, 1);
+        $forum_auth = $auth_cache[$pos];
         if ($forum_auth == $one_char_encoding) {
             $auth_len = 1;
             continue;
@@ -166,7 +166,7 @@ function is_forum_authed($auth_cache, $check_forum_id)
     $auth_len = 1;
 
     for ($pos = 0; $pos < strlen($auth_cache); $pos += $auth_len) {
-        $forum_auth = substr($auth_cache, $pos, 1);
+        $forum_auth = $auth_cache[$pos];
         if ($forum_auth == $one_char_encoding) {
             $auth_len = 1;
             continue;
diff --git a/library/includes/classes/correct.php b/library/includes/classes/correct.php
index c0b9722d2..7edbeb93e 100644
--- a/library/includes/classes/correct.php
+++ b/library/includes/classes/correct.php
@@ -2956,7 +2956,7 @@ class Text_LangCorrect
             */
 
             #0a. английский --> русский:
-            if (substr($word, 1, 1) === '.'  #оптимизация
+            if ($word[1] === '.'  #оптимизация
                 && preg_match('/^ (  ' . $this->en_similar_uc . '\.         #первый инициал
                                      (?:' . $this->en_similar_uc . '\.)?    #второй инициал (необязательно)
                                   )                                       #1 инициалы
@@ -2973,7 +2973,7 @@ class Text_LangCorrect
             }
 
             #0b. русский --> английский:
-            if (substr($word, 2, 1) === '.'  #оптимизация
+            if ($word[2] === '.'  #оптимизация
                 && preg_match('/^ (  ' . $this->ru_similar_uc . '\.         #первый инициал
                                      (?:' . $this->ru_similar_uc . '\.)?    #второй инициал (необязательно)
                                   )                                       #1 инициалы
diff --git a/library/includes/smtp.php b/library/includes/smtp.php
index 672fbbb5e..c138bca1e 100644
--- a/library/includes/smtp.php
+++ b/library/includes/smtp.php
@@ -32,7 +32,7 @@ define('SMTP_INCLUDED', 1);
 function server_parse($socket, $response, $line = __LINE__)
 {
     $server_response = '';
-    while (substr($server_response, 3, 1) != ' ') {
+    while ($server_response[3] != ' ') {
         if (!($server_response = fgets($socket, 256))) {
             bb_die('Could not get mail server response codes');
         }
diff --git a/library/includes/template.php b/library/includes/template.php
index 58eba0ed3..3e4fe5e0d 100644
--- a/library/includes/template.php
+++ b/library/includes/template.php
@@ -173,7 +173,7 @@ class template
             $filename = $this->replace[$filename];
         }
         // Check if it's an absolute or relative path.
-        if ((substr($filename, 0, 1) !== '/') && (substr($filename, 1, 1) !== ':')) {
+        if (($filename[0] !== '/') && ($filename[1] !== ':')) {
             return $this->root . '/' . $filename;
         }