diff --git a/.gitignore b/.gitignore
index aa95de5ab..4a8a96d0a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 ### TorrentPier ###
+.vagrant
 .idea
 bower_components
 composer.phar
diff --git a/admin/admin_forums.php b/admin/admin_forums.php
index 81b870476..f77806c11 100644
--- a/admin/admin_forums.php
+++ b/admin/admin_forums.php
@@ -56,7 +56,7 @@ $default_forum_auth = [
     'auth_download' => AUTH_REG,
 ];
 
-$mode = ($_REQUEST['mode']) ? (string)$_REQUEST['mode'] : '';
+$mode = isset($_REQUEST['mode']) ? (string)$_REQUEST['mode'] : '';
 
 $cat_forums = get_cat_forums();
 
diff --git a/library/defines.php b/library/defines.php
index 486a75abe..6560668e2 100644
--- a/library/defines.php
+++ b/library/defines.php
@@ -55,7 +55,7 @@ define('TEMPLATES_DIR', BB_PATH . '/styles/templates/');
 define('ADMIN_TPL_DIR', TEMPLATES_DIR . '/admin/');
 
 // Debug
-define('DBG_LOG', false);    // enable forum debug (off on production)
+define('DBG_LOG', true);    // enable forum debug (off on production)
 define('DBG_TRACKER', false);    // enable tracker debug (off on production)
 define('COOKIE_DBG', 'bb_dbg'); // debug cookie name
 define('SQL_DEBUG', true);     // enable forum sql & cache debug
@@ -72,9 +72,9 @@ define('LOG_LF', "\n");
 define('LOG_MAX_SIZE', 1048576); // bytes
 
 // Error reporting
-ini_set('error_reporting', E_ALL);
-ini_set('display_errors', 0);
-ini_set('log_errors', 1);
+//ini_set('error_reporting', E_ALL);
+//ini_set('display_errors', 0);
+//ini_set('log_errors', 1);
 ini_set('error_log', LOG_DIR . 'php_err.log');
 
 // Triggers
diff --git a/library/includes/bbcode.php b/library/includes/bbcode.php
index cb2588b1f..8710d1473 100644
--- a/library/includes/bbcode.php
+++ b/library/includes/bbcode.php
@@ -500,7 +500,7 @@ class bbcode
     /**
      * Constructor
      */
-    public function bbcode()
+    public function __construct()
     {
         $this->tpl = get_bbcode_tpl();
 
@@ -900,7 +900,7 @@ class words_rate
     public $words_del_exp = '';
     public $words_cnt_exp = '#[a-zA-Zа-яА-ЯёЁ]{4,}#';
 
-    public function words_rate()
+    public function __construct()
     {
         // слова начинающиеся на..
         $del_list = file_get_contents(BB_ROOT . '/library/words_rate_del_list.txt');
diff --git a/library/includes/core/mysql.php b/library/includes/core/mysql.php
index 981ab25e2..d6a81b3c3 100644
--- a/library/includes/core/mysql.php
+++ b/library/includes/core/mysql.php
@@ -65,7 +65,7 @@ class sql_db
      * @param $cfg_values
      * @return sql_db
      */
-    public function sql_db($cfg_values)
+    public function __construct($cfg_values)
     {
         global $DBS;
 
@@ -94,7 +94,7 @@ class sql_db
         $this->selected_db = $this->select_db();
 
         // Set charset
-        if ($this->cfg['charset'] && !mysql_set_charset($this->cfg['charset'], $this->link)) {
+        if ($this->cfg['charset'] && !mysqli_set_charset($this->link, $this->cfg['charset'])) {
             if (!$this->sql_query("SET NAMES {$this->cfg['charset']}")) {
                 die("Could not set charset {$this->cfg['charset']}");
             }
@@ -113,10 +113,7 @@ class sql_db
     {
         $this->cur_query = ($this->dbg_enabled) ? ($this->cfg['persist'] ? 'p' : '') . "connect to: {$this->cfg['dbhost']}" : 'connect';
         $this->debug('start');
-
-        $connect_type = ($this->cfg['persist']) ? 'mysql_pconnect' : 'mysql_connect';
-
-        if (!$link = $connect_type($this->cfg['dbhost'], $this->cfg['dbuser'], $this->cfg['dbpasswd'])) {
+        if (!$link = mysqli_connect($this->cfg['dbhost'], $this->cfg['dbuser'], $this->cfg['dbpasswd'], $this->cfg['dbname'])) {
             $server = (DBG_USER) ? $this->cfg['dbhost'] : '';
             header("HTTP/1.0 503 Service Unavailable");
             bb_log(' ', "db_err/connect_failed_{$this->cfg['dbhost']}");
@@ -139,10 +136,10 @@ class sql_db
         $this->cur_query = ($this->dbg_enabled) ? "select db: {$this->cfg['dbname']}" : 'select db';
         $this->debug('start');
 
-        if (!mysql_select_db($this->cfg['dbname'], $this->link)) {
-            $database = (DBG_USER) ? $this->cfg['dbhost'] : '';
-            die("Could not select database $database");
-        }
+//        if (!mysqli_select_db($this->link, $this->cfg['dbname'])) {
+//            $database = (DBG_USER) ? $this->cfg['dbhost'] : '';
+//            die("Could not select database $database");
+//        }
 
         $this->debug('stop');
         $this->cur_query = null;
@@ -157,7 +154,7 @@ class sql_db
      */
     public function sql_query($query)
     {
-        if (!is_resource($this->link)) {
+        if ($this->link) {
             $this->init();
         }
         if (is_array($query)) {
@@ -169,7 +166,7 @@ class sql_db
         $this->cur_query = $query;
         $this->debug('start');
 
-        if (!$this->result = mysql_query($query, $this->link)) {
+        if (!$this->result = mysqli_query($this->link, $query)) {
             $this->log_error();
         }
 
@@ -208,7 +205,7 @@ class sql_db
         $num_rows = false;
 
         if ($result or $result = $this->result) {
-            $num_rows = is_resource($result) ? mysql_num_rows($result) : false;
+            $num_rows = $result instanceof mysqli_result ? mysqli_num_rows($result) : false;
         }
 
         return $num_rows;
@@ -219,7 +216,7 @@ class sql_db
      */
     public function affected_rows()
     {
-        return is_resource($this->link) ? mysql_affected_rows($this->link) : -1;
+        return $this->link ? mysqli_affected_rows($this->link) : -1;
     }
 
     /**
@@ -236,7 +233,7 @@ class sql_db
         }
         if ($query_id) {
             if ($rownum > -1) {
-                $result = mysql_result($query_id, $rownum, $field);
+                $result = mysqli_result($query_id, $rownum, $field);
             } else {
                 if (empty($this->row[$query_id]) && empty($this->rowset[$query_id])) {
                     if ($this->sql_fetchrow()) {
@@ -264,7 +261,7 @@ class sql_db
      */
     public function sql_fetchrow($result, $field_name = '')
     {
-        $row = mysql_fetch_assoc($result);
+        $row = mysqli_fetch_assoc($result);
 
         if ($field_name) {
             return isset($row[$field_name]) ? $row[$field_name] : false;
@@ -308,7 +305,7 @@ class sql_db
     {
         $rowset = array();
 
-        while ($row = mysql_fetch_assoc($result)) {
+        while ($row = mysqli_fetch_assoc($result)) {
             $rowset[] = ($field_name) ? $row[$field_name] : $row;
         }
 
@@ -350,7 +347,7 @@ class sql_db
      */
     public function sql_nextid()
     {
-        return mysql_insert_id($this->link);
+        return mysqli_insert_id($this->link);
     }
 
     /**
@@ -360,7 +357,7 @@ class sql_db
     public function sql_freeresult($result = false)
     {
         if ($result or $result = $this->result) {
-            $return_value = is_resource($result) ? mysql_free_result($result) : false;
+            $return_value = is_resource($result) ? mysqli_free_result($result) : false;
         }
 
         $this->result = null;
@@ -405,11 +402,11 @@ class sql_db
      */
     public function escape_string($str)
     {
-        if (!is_resource($this->link)) {
+        if (!$this->link) {
             $this->init();
         }
 
-        return mysql_real_escape_string($str, $this->link);
+        return mysqli_real_escape_string($this->link, $str);
     }
 
     /**
@@ -542,8 +539,8 @@ class sql_db
      */
     public function sql_error()
     {
-        if (is_resource($this->link)) {
-            return array('code' => mysql_errno($this->link), 'message' => mysql_error($this->link));
+        if ($this->link) {
+            return array('code' => mysqli_errno($this->link), 'message' => mysqli_error($this->link));
         } else {
             return array('code' => '', 'message' => 'not connected');
         }
@@ -554,7 +551,7 @@ class sql_db
      */
     public function close()
     {
-        if (is_resource($this->link)) {
+        if ($this->link) {
             $this->unlock();
 
             if (!empty($this->locks)) {
@@ -565,7 +562,7 @@ class sql_db
 
             $this->exec_shutdown_queries();
 
-            mysql_close($this->link);
+            mysqli_close($this->link);
         }
 
         $this->link = $this->selected_db = null;
@@ -710,7 +707,7 @@ class sql_db
             $info[] = "$num rows";
         }
 
-        if (is_resource($this->link) and $ext = mysql_info($this->link)) {
+        if ($this->link and $ext = mysqli_info($this->link)) {
             $info[] = "$ext";
         } elseif (!$num && ($aff = $this->affected_rows($this->result) and $aff != -1)) {
             $info[] = "$aff rows";
@@ -724,7 +721,7 @@ class sql_db
      */
     public function server_version()
     {
-        preg_match('#^(\d+\.\d+\.\d+).*#', mysql_get_server_info(), $m);
+        preg_match('#^(\d+\.\d+\.\d+).*#', mysqli_get_server_info(), $m);
         return $m[1];
     }
 
@@ -953,8 +950,8 @@ class sql_db
                 if (preg_match('#^SELECT#', $query)) {
                     $html_table = false;
 
-                    if ($result = mysql_query("EXPLAIN $query", $this->link)) {
-                        while ($row = mysql_fetch_assoc($result)) {
+                    if ($result = mysqli_query($this->link, "EXPLAIN $query")) {
+                        while ($row = mysqli_fetch_assoc($result)) {
                             $html_table = $this->explain('add_explain_row', $html_table, $row);
                         }
                     }
diff --git a/library/includes/functions.php b/library/includes/functions.php
index 3ef326e43..6f4962e49 100644
--- a/library/includes/functions.php
+++ b/library/includes/functions.php
@@ -551,7 +551,7 @@ class Date_Delta
     /**
      * Date_Delta constructor.
      */
-    public function Date_Delta()
+    public function __construct()
     {
         global $lang;
 
diff --git a/library/includes/online_userlist.php b/library/includes/online_userlist.php
index 3c98bd529..3fcf20bd1 100644
--- a/library/includes/online_userlist.php
+++ b/library/includes/online_userlist.php
@@ -59,11 +59,11 @@ $online = $online_short = array('userlist' => '');
 $sql = "
 	SELECT
 		u.username, u.user_id, u.user_opt, u.user_rank, u.user_level,
-		s.session_logged_in, s.session_ip, (s.session_time - s.session_start) AS ses_len, COUNT(s.session_id) AS sessions, COUNT(DISTINCT s.session_ip) AS ips
+		s.session_logged_in, s.session_ip, MAX(s.session_time - s.session_start) AS ses_len, COUNT(s.session_id) AS sessions, COUNT(DISTINCT s.session_ip) AS ips
 	FROM " . BB_SESSIONS . " s, " . BB_USERS . " u
 	WHERE s.session_time > $time_online
 		AND u.user_id = s.session_user_id
-	GROUP BY s.session_user_id
+	GROUP BY s.session_user_id, s.session_logged_in, s.session_ip
 	ORDER BY u.username
 ";
 
diff --git a/library/includes/sessions.php b/library/includes/sessions.php
index ba0c375c5..bd5e62dcd 100644
--- a/library/includes/sessions.php
+++ b/library/includes/sessions.php
@@ -90,7 +90,7 @@ class user_common
     /**
      *  Constructor
      */
-    public function user_common()
+    public function __construct()
     {
         $this->get_sessiondata();
     }
diff --git a/library/includes/template.php b/library/includes/template.php
index 0836ff3e2..9e9413845 100644
--- a/library/includes/template.php
+++ b/library/includes/template.php
@@ -117,7 +117,7 @@ class template
      * @param string $root
      * @return template
      */
-    public function Template($root = '.')
+    public function __construct($root = '.')
     {
         global $lang;
 
@@ -953,8 +953,8 @@ class template
                     break;
 
                 case 'is':
-                    $is_arg_start = ($tokens[$i - 1] == ')') ? array_pop($is_arg_stack) : $i - 1;
-                    $is_arg = join('	', array_slice($tokens, $is_arg_start, $i - $is_arg_start));
+                    $is_arg_start = ($tokens[$i - 1] === ')') ? array_pop($is_arg_stack) : $i - 1;
+                    $is_arg = implode('	', array_slice($tokens, $is_arg_start, $i - $is_arg_start));
 
                     $new_tokens = $this->_parse_is_expr($is_arg, array_slice($tokens, $i + 1));
 
@@ -1009,7 +1009,7 @@ class template
         $expr_end = 0;
         $negate_expr = false;
 
-        if (($first_token = array_shift($tokens)) == 'not') {
+        if (($first_token = array_shift($tokens)) === 'not') {
             $negate_expr = true;
             $expr_type = array_shift($tokens);
         } else {
@@ -1018,7 +1018,7 @@ class template
 
         switch ($expr_type) {
             case 'even':
-                if ($tokens[$expr_end] == 'by') {
+                if ($tokens[$expr_end] === 'by') {
                     $expr_end++;
                     $expr_arg = $tokens[$expr_end++];
                     $expr = "!(($is_arg	/ $expr_arg) % $expr_arg)";
@@ -1028,7 +1028,7 @@ class template
                 break;
 
             case 'odd':
-                if ($tokens[$expr_end] == 'by') {
+                if ($tokens[$expr_end] === 'by') {
                     $expr_end++;
                     $expr_arg = $tokens[$expr_end++];
                     $expr = "(($is_arg / $expr_arg)	% $expr_arg)";
@@ -1038,7 +1038,7 @@ class template
                 break;
 
             case 'div':
-                if ($tokens[$expr_end] == 'by') {
+                if ($tokens[$expr_end] === 'by') {
                     $expr_end++;
                     $expr_arg = $tokens[$expr_end++];
                     $expr = "!($is_arg % $expr_arg)";
diff --git a/library/includes/ucp/viewtorrent.php b/library/includes/ucp/viewtorrent.php
index babaf70aa..fd9aaf842 100644
--- a/library/includes/ucp/viewtorrent.php
+++ b/library/includes/ucp/viewtorrent.php
@@ -49,7 +49,6 @@ $sql = DB()->fetch_rowset("
 		AND tor.topic_id = t.topic_id
 		AND t.forum_id = f.forum_id
 			$not_auth_forums_sql
-	GROUP BY tr.topic_id
 	ORDER BY f.forum_name, t.topic_title
 ");
 
diff --git a/posting.php b/posting.php
index be49f079f..fbddbd8cf 100644
--- a/posting.php
+++ b/posting.php
@@ -42,9 +42,9 @@ $submit = $di->request->request->has('post');
 $preview = $di->request->request->has('preview');
 $delete = $di->request->request->has('delete');
 
-$forum_id = $di->request->request->getInt(POST_FORUM_URL);
-$topic_id = $di->request->request->getInt(POST_TOPIC_URL);
-$post_id = $di->request->request->getInt(POST_POST_URL);
+$forum_id = $di->request->query->getInt(POST_FORUM_URL);
+$topic_id = $di->request->query->getInt(POST_TOPIC_URL);
+$post_id = $di->request->query->getInt(POST_POST_URL);
 
 $mode = (string)$_REQUEST['mode'];
 
@@ -628,7 +628,7 @@ if ($mode == 'newtopic' || $post_data['first_post']) {
         'S_FORM_ENCTYPE' => 'enctype="multipart/form-data"',
         'FILE_ATTACHED' => $file_attached,
         'ATTACH_MAX_SIZE' => humn_size($di->config->get('attach.max_size')),
-        'ALLOWED_EXT' => ($allowed_ext) ? '*.' . join(', *.', $allowed_ext) : 'прикреплять запрещено', // TODO: перевести
+        'ALLOWED_EXT' => ($allowed_ext) ? '*.' . implode(', *.', $allowed_ext) : 'прикреплять запрещено', // TODO: перевести
         'TOR_REQUIRED' => !empty($_POST['tor_required']),
         'POLL_TIP' => ($mode == 'newtopic') ? 'Вы сможете добавить опрос после создания темы' : 'Вы можете добавить опрос со страницы просмотра темы', // TODO: перевести
     ));
diff --git a/viewforum.php b/viewforum.php
index 1b9f3d494..c776298ad 100644
--- a/viewforum.php
+++ b/viewforum.php
@@ -169,7 +169,6 @@ if (!$forum_data['forum_parent'] && isset($forums['f'][$forum_id]['subforums'])
 		WHERE f.forum_parent = $forum_id
 			$only_new_sql
 			$ignore_forum_sql
-		GROUP BY f.forum_id
 		ORDER BY f.forum_order
 	";
 
diff --git a/viewtopic.php b/viewtopic.php
index f0a68b43d..bd969b229 100644
--- a/viewtopic.php
+++ b/viewtopic.php
@@ -590,9 +590,23 @@ for ($i = 0; $i < $total_posts; $i++) {
     // Replace naughty words
     if (count($orig_word)) {
         if ($user_sig) {
-            $user_sig = str_replace('\"', '"', substr(preg_replace('#(\>(((?>([^><]+|(?R)))*)\<))#se', "@preg_replace(\$orig_word, \$replacement_word, '\\0')", '>' . $user_sig . '<'), 1, -1));
+            $user_sig = str_replace(
+                '\"', '"',
+                    substr(
+                        preg_replace_callback('#(\>(((?>([^><]+|(?R)))*)\<))#s', function ($matches) use ($orig_word, $replacement_word) {
+                            return preg_replace($orig_word, $replacement_word, $matches[0]);
+                        }, '>' . $user_sig . '<'), 1, -1
+                    )
+            );
         }
-        $message = str_replace('\"', '"', substr(preg_replace('#(\>(((?>([^><]+|(?R)))*)\<))#se', "@preg_replace(\$orig_word, \$replacement_word, '\\0')", '>' . $message . '<'), 1, -1));
+        $message = str_replace(
+            '\"', '"',
+            substr(
+                preg_replace_callback('#(\>(((?>([^><]+|(?R)))*)\<))#s', function ($matches) use ($orig_word, $replacement_word) {
+                    return preg_replace($orig_word, $replacement_word, $matches[0]);
+                }, '>' . $message . '<'), 1, -1
+            )
+        );
     }
 
     // Replace newlines (we use this rather than nl2br because till recently it wasn't XHTML compliant)