diff --git a/phpBB/includes/acp/acp_users.php b/phpBB/includes/acp/acp_users.php
index 3a405da825..1f10893781 100644
--- a/phpBB/includes/acp/acp_users.php
+++ b/phpBB/includes/acp/acp_users.php
@@ -231,6 +231,11 @@ class acp_users
 								trigger_error($user->lang['CANNOT_BAN_YOURSELF'] . adm_back_link($this->u_action . '&u=' . $user_id), E_USER_WARNING);
 							}
 
+							if ($user_id == ANONYMOUS)
+							{
+								trigger_error($user->lang['CANNOT_BAN_ANONYMOUS'] . adm_back_link($this->u_action . '&u=' . $user_id), E_USER_WARNING);
+							}
+
 							if ($user_row['user_type'] == USER_FOUNDER)
 							{
 								trigger_error($user->lang['CANNOT_BAN_FOUNDER'] . adm_back_link($this->u_action . '&u=' . $user_id), E_USER_WARNING);
diff --git a/phpBB/includes/db/firebird.php b/phpBB/includes/db/firebird.php
index e554b0f2fb..6f60dd5dad 100644
--- a/phpBB/includes/db/firebird.php
+++ b/phpBB/includes/db/firebird.php
@@ -63,10 +63,19 @@ class dbal_firebird extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache forced to false for Interbase
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
+		/**
+		* force $use_cache false.  I didn't research why the caching code there is no caching code
+		* but I assume its because the IB extension provides a direct method to access it
+		* without a query.
+		*/
+
+		$use_cache = false;
+
 		if ($this->service_handle !== false && function_exists('ibase_server_info'))
 		{
 			return @ibase_server_info($this->service_handle, IBASE_SVC_SERVER_VERSION);
diff --git a/phpBB/includes/db/mssql.php b/phpBB/includes/db/mssql.php
index 7134574691..6899a73902 100644
--- a/phpBB/includes/db/mssql.php
+++ b/phpBB/includes/db/mssql.php
@@ -65,13 +65,14 @@ class dbal_mssql extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
 		{
 			$result_id = @mssql_query("SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY('productlevel'), SERVERPROPERTY('edition')", $this->db_connect_id);
 
@@ -84,7 +85,7 @@ class dbal_mssql extends dbal
 
 			$this->sql_server_version = ($row) ? trim(implode(' ', $row)) : 0;
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('mssql_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/mssql_odbc.php b/phpBB/includes/db/mssql_odbc.php
index 14c4831010..75a080b1b7 100644
--- a/phpBB/includes/db/mssql_odbc.php
+++ b/phpBB/includes/db/mssql_odbc.php
@@ -76,13 +76,14 @@ class dbal_mssql_odbc extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('mssqlodbc_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssqlodbc_version')) === false)
 		{
 			$result_id = @odbc_exec($this->db_connect_id, "SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY('productlevel'), SERVERPROPERTY('edition')");
 
@@ -95,7 +96,7 @@ class dbal_mssql_odbc extends dbal
 
 			$this->sql_server_version = ($row) ? trim(implode(' ', $row)) : 0;
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('mssqlodbc_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/mssqlnative.php b/phpBB/includes/db/mssqlnative.php
index 08ee70907c..98e22d4412 100644
--- a/phpBB/includes/db/mssqlnative.php
+++ b/phpBB/includes/db/mssqlnative.php
@@ -232,18 +232,19 @@ class dbal_mssqlnative extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
 		{
 			$arr_server_info = sqlsrv_server_info($this->db_connect_id);
 			$this->sql_server_version = $arr_server_info['SQLServerVersion'];
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('mssql_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/mysql.php b/phpBB/includes/db/mysql.php
index 0487dfa6d2..1e24c79577 100644
--- a/phpBB/includes/db/mysql.php
+++ b/phpBB/includes/db/mysql.php
@@ -96,13 +96,14 @@ class dbal_mysql extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('mysql_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mysql_version')) === false)
 		{
 			$result = @mysql_query('SELECT VERSION() AS version', $this->db_connect_id);
 			$row = @mysql_fetch_assoc($result);
@@ -110,7 +111,7 @@ class dbal_mysql extends dbal
 
 			$this->sql_server_version = $row['version'];
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('mysql_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/mysqli.php b/phpBB/includes/db/mysqli.php
index f0e58fd148..862d62f4ba 100644
--- a/phpBB/includes/db/mysqli.php
+++ b/phpBB/includes/db/mysqli.php
@@ -80,14 +80,14 @@ class dbal_mysqli extends dbal
 
 	/**
 	* Version information about used database
-	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('mysqli_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mysqli_version')) === false)
 		{
 			$result = @mysqli_query($this->db_connect_id, 'SELECT VERSION() AS version');
 			$row = @mysqli_fetch_assoc($result);
@@ -95,7 +95,7 @@ class dbal_mysqli extends dbal
 
 			$this->sql_server_version = $row['version'];
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('mysqli_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/oracle.php b/phpBB/includes/db/oracle.php
index 5a9b18abf0..c8a9a5f604 100644
--- a/phpBB/includes/db/oracle.php
+++ b/phpBB/includes/db/oracle.php
@@ -56,10 +56,18 @@ class dbal_oracle extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache forced to false for Oracle
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
+		/**
+		* force $use_cache false.  I didn't research why the caching code below is commented out
+		* but I assume its because the Oracle extension provides a direct method to access it
+		* without a query.
+		*/
+
+		$use_cache = false;
 /*
 		global $cache;
 
diff --git a/phpBB/includes/db/postgres.php b/phpBB/includes/db/postgres.php
index 2a885f1d04..4360c790a1 100644
--- a/phpBB/includes/db/postgres.php
+++ b/phpBB/includes/db/postgres.php
@@ -108,13 +108,14 @@ class dbal_postgres extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache If true, it is safe to retrieve the value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('pgsql_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('pgsql_version')) === false)
 		{
 			$query_id = @pg_query($this->db_connect_id, 'SELECT VERSION() AS version');
 			$row = @pg_fetch_assoc($query_id, null);
@@ -122,7 +123,7 @@ class dbal_postgres extends dbal
 
 			$this->sql_server_version = (!empty($row['version'])) ? trim(substr($row['version'], 10)) : 0;
 
-			if (!empty($cache))
+			if (!empty($cache) && $use_cache)
 			{
 				$cache->put('pgsql_version', $this->sql_server_version);
 			}
diff --git a/phpBB/includes/db/sqlite.php b/phpBB/includes/db/sqlite.php
index 288f6e0992..8de72fd394 100644
--- a/phpBB/includes/db/sqlite.php
+++ b/phpBB/includes/db/sqlite.php
@@ -50,19 +50,24 @@ class dbal_sqlite extends dbal
 	/**
 	* Version information about used database
 	* @param bool $raw if true, only return the fetched sql_server_version
+	* @param bool $use_cache if true, it is safe to retrieve the stored value from the cache
 	* @return string sql server version
 	*/
-	function sql_server_info($raw = false)
+	function sql_server_info($raw = false, $use_cache = true)
 	{
 		global $cache;
 
-		if (empty($cache) || ($this->sql_server_version = $cache->get('sqlite_version')) === false)
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('sqlite_version')) === false)
 		{
 			$result = @sqlite_query('SELECT sqlite_version() AS version', $this->db_connect_id);
 			$row = @sqlite_fetch_array($result, SQLITE_ASSOC);
 
 			$this->sql_server_version = (!empty($row['version'])) ? $row['version'] : 0;
-			$cache->put('sqlite_version', $this->sql_server_version);
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('sqlite_version', $this->sql_server_version);
+			}
 		}
 
 		return ($raw) ? $this->sql_server_version : 'SQLite ' . $this->sql_server_version;
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index d88960ff1d..fe80880789 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -4318,7 +4318,7 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 		'T_ICONS_PATH'			=> "{$web_path}{$config['icons_path']}/",
 		'T_RANKS_PATH'			=> "{$web_path}{$config['ranks_path']}/",
 		'T_UPLOAD_PATH'			=> "{$web_path}{$config['upload_path']}/",
-		'T_STYLESHEET_LINK'		=> (!$user->theme['theme_storedb']) ? "{$web_path}styles/" . $user->theme['theme_path'] . '/theme/stylesheet.css' : append_sid("{$phpbb_root_path}style.$phpEx", 'id=' . $user->theme['style_id'] . '&lang=' . $user->data['user_lang'], true, $user->session_id),
+		'T_STYLESHEET_LINK'		=> (!$user->theme['theme_storedb']) ? "{$web_path}styles/" . $user->theme['theme_path'] . '/theme/stylesheet.css' : append_sid("{$phpbb_root_path}style.$phpEx", 'id=' . $user->theme['style_id'] . '&lang=' . $user->data['user_lang']),
 		'T_STYLESHEET_NAME'		=> $user->theme['theme_name'],
 
 		'T_THEME_NAME'			=> $user->theme['theme_path'],
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index bb99314ced..6f6d7526b7 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -837,14 +837,15 @@ function user_ban($mode, $ban, $ban_len, $ban_len_other, $ban_exclude, $ban_reas
 				FROM ' . USERS_TABLE . '
 				WHERE ' . $db->sql_in_set('username_clean', $sql_usernames);
 
-			// Do not allow banning yourself
+			// Do not allow banning yourself, the guest account, or founders.
+			$non_bannable = array($user->data['user_id'], ANONYMOUS);
 			if (sizeof($founder))
 			{
-				$sql .= ' AND ' . $db->sql_in_set('user_id', array_merge(array_keys($founder), array($user->data['user_id'])), true);
+				$sql .= ' AND ' . $db->sql_in_set('user_id', array_merge(array_keys($founder), $non_bannable), true);
 			}
 			else
 			{
-				$sql .= ' AND user_id <> ' . $user->data['user_id'];
+				$sql .= ' AND ' . $db->sql_in_set('user_id', $non_bannable, true);
 			}
 
 			$result = $db->sql_query($sql);
diff --git a/phpBB/install/install_convert.php b/phpBB/install/install_convert.php
index 06c3a8b4a6..8c3ffd61a8 100644
--- a/phpBB/install/install_convert.php
+++ b/phpBB/install/install_convert.php
@@ -685,7 +685,7 @@ class install_convert extends module
 			// Thanks MySQL, for silently converting...
 			case 'mysql':
 			case 'mysql4':
-				if (version_compare($src_db->sql_server_info(true), '4.1.3', '>='))
+				if (version_compare($src_db->sql_server_info(true, false), '4.1.3', '>='))
 				{
 					$convert->mysql_convert = true;
 				}
diff --git a/phpBB/language/en/acp/users.php b/phpBB/language/en/acp/users.php
index 8d9bf0d486..eda9659795 100644
--- a/phpBB/language/en/acp/users.php
+++ b/phpBB/language/en/acp/users.php
@@ -42,6 +42,7 @@ $lang = array_merge($lang, array(
 	'BAN_ALREADY_ENTERED'	=> 'The ban had been previously entered successfully. The ban list has not been updated.',
 	'BAN_SUCCESSFUL'		=> 'Ban entered successfully.',
 
+	'CANNOT_BAN_ANONYMOUS'			=> 'You are not allowed to ban the anonymous account. Permissions for anonymous users can be set under the Permissions tab.',
 	'CANNOT_BAN_FOUNDER'			=> 'You are not allowed to ban founder accounts.',
 	'CANNOT_BAN_YOURSELF'			=> 'You are not allowed to ban yourself.',
 	'CANNOT_DEACTIVATE_BOT'			=> 'You are not allowed to deactivate bot accounts. Please deactivate the bot within the bots page instead.',
diff --git a/phpBB/style.php b/phpBB/style.php
index fa77815670..8ca1751391 100644
--- a/phpBB/style.php
+++ b/phpBB/style.php
@@ -45,15 +45,8 @@ if (!empty($load_extensions) && function_exists('dl'))
 	}
 }
 
-
-$sid = (isset($_GET['sid']) && !is_array($_GET['sid'])) ? htmlspecialchars($_GET['sid']) : '';
 $id = (isset($_GET['id'])) ? intval($_GET['id']) : 0;
 
-if (strspn($sid, 'abcdefABCDEF0123456789') !== strlen($sid))
-{
-	$sid = '';
-}
-
 // This is a simple script to grab and output the requested CSS data stored in the DB
 // We include a session_id check to try and limit 3rd party linking ... unless they
 // happen to have a current session it will output nothing. We will also cache the
@@ -81,6 +74,20 @@ if ($id)
 	$config = $cache->obtain_config();
 	$user = false;
 
+	// try to get a session ID from REQUEST array
+	$sid = request_var('sid', '');
+
+	if (!$sid)
+	{
+		// if that failed, then look in the cookies
+		$sid = request_var($config['cookie_name'] . '_sid', '', false, true);
+	}
+
+	if (strspn($sid, 'abcdefABCDEF0123456789') !== strlen($sid))
+	{
+		$sid = '';
+	}
+
 	if ($sid)
 	{
 		$sql = 'SELECT u.user_id, u.user_lang