diff --git a/phpBB/includes/acp/acp_board.php b/phpBB/includes/acp/acp_board.php
index 7ed08d0136..8f29fdf43f 100644
--- a/phpBB/includes/acp/acp_board.php
+++ b/phpBB/includes/acp/acp_board.php
@@ -679,13 +679,12 @@ class acp_board
 	{
 		global $user;
 
-		$user_char_ary = array('USERNAME_CHARS_ANY' => '.*', 'USERNAME_ALPHA_ONLY' => '[a-z]+', 'USERNAME_ALPHA_SPACERS' => '[-\]_+ [a-z]+', 'USERNAME_LETTER_NUM' => '\w+', 'USERNAME_LETTER_NUM_SPACERS' => '[-\]_+ [\w]+', 'USERNAME_ASCII' => '[\x01-\x7F]+');
-
+		$user_char_ary = array('USERNAME_CHARS_ANY', 'USERNAME_ALPHA_ONLY', 'USERNAME_ALPHA_SPACERS', 'USERNAME_LETTER_NUM', 'USERNAME_LETTER_NUM_SPACERS', 'USERNAME_ASCII');
 		$user_char_options = '';
-		foreach ($user_char_ary as $lang => $value)
+		foreach ($user_char_ary as $user_type)
 		{
-			$selected = ($selected_value == $value) ? ' selected="selected"' : '';
-			$user_char_options .= '<option value="' . $value . '"' . $selected . '>' . $user->lang[$lang] . '</option>';
+			$selected = ($selected_value == $user_type) ? ' selected="selected"' : '';
+			$user_char_options .= '<option value="' . $user_type . '"' . $selected . '>' . $user->lang[$user_type] . '</option>';
 		}
 
 		return $user_char_options;
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index 1f17274250..cccebfbc56 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1184,7 +1184,92 @@ function validate_username($username, $allowed_username = false)
 		return false;
 	}
 
-	if (!preg_match('#^' . str_replace('\\\\', '\\', $config['allow_name_chars']) . '$#ui', $username) || strpos($username, '&quot;') !== false || strpos($username, '"') !== false)
+	$mbstring = $pcre = false;
+
+	// generic UTF-8 character types supported?
+	if (version_compare(PHP_VERSION, '5.1.0', '>=') || (version_compare(PHP_VERSION, '5.0.0-dev', '<=') && version_compare(PHP_VERSION, '4.4.0', '>=')))
+	{
+		$pcre = true;
+	}
+	else if (function_exists('mb_ereg_match'))
+	{
+		mb_regex_encoding('UTF-8');
+		$mbstring = true;
+	}
+
+	switch ($config['allow_name_chars'])
+	{
+		case 'USERNAME_CHARS_ANY':
+			$pcre = true;
+			$regex = '.+';
+		break;
+
+		case 'USERNAME_ALPHA_ONLY':
+			$pcre = true;
+			$regex = '[A-Za-z]+';
+		break;
+
+		case 'USERNAME_ALPHA_SPACERS':
+			$pcre = true;
+			$regex = '[-\]_+ ]+';
+		break;
+
+		case 'USERNAME_LETTER_NUM':
+			if ($pcre)
+			{
+				$regex = '[\p{Lu}\p{Ll}\p{N}]+';
+			}
+			else if ($mbstring)
+			{
+				$regex = '[[:upper:][:lower:][:digit:]]+';
+			}
+			else
+			{
+				$pcre = true;
+				$regex = '[a-zA-Z0-9]+';
+			}
+		break;
+
+		case 'USERNAME_LETTER_NUM_SPACERS':
+			if ($pcre)
+			{
+				$regex = '[-\]_+ [\p{Lu}\p{Ll}\p{N}]+';
+			}
+			else if ($mbstring)
+			{
+				$regex = '[-\]_+ [[:upper:][:lower:][:digit:]]+';
+			}
+			else
+			{
+				$pcre = true;
+				$regex = '[-\]_+ [a-zA-Z0-9]+';
+			}
+		break;
+
+		case 'USERNAME_ASCII':
+			$pcre = true;
+			$regex = '[\x01-\x7F]+';
+		break;
+	}
+
+	if ($pcre)
+	{
+		if (!preg_match('#^' . $regex . '$#u', $username))
+		{
+			return 'INVALID_CHARS';
+		}
+	}
+	else if ($mbstring)
+	{
+		$matches = array();
+		mb_ereg_search_init('^' . $username . '$', $regex, $matches);
+		if (!mb_ereg_search())
+		{
+			return 'INVALID_CHARS';
+		}
+	}
+
+	if (strpos($username, '&quot;') !== false || strpos($username, '"') !== false)
 	{
 		return 'INVALID_CHARS';
 	}
diff --git a/phpBB/install/database_update.php b/phpBB/install/database_update.php
index 5ec0f8ffd2..d7bd1b3782 100644
--- a/phpBB/install/database_update.php
+++ b/phpBB/install/database_update.php
@@ -1037,6 +1037,10 @@ if (version_compare($current_version, '3.0.b5', '<='))
 		$db->sql_query($sql);
 	}
 
+	$user_char_ary = array('.*' => 'USERNAME_CHARS_ANY', '[a-z]+' => 'USERNAME_ALPHA_ONLY', '[-\]_+ [a-z]+' => 'USERNAME_ALPHA_SPACERS', '\w+' => 'USERNAME_LETTER_NUM', '[-\]_+ [\w]+' => 'USERNAME_LETTER_NUM_SPACERS', '[\x01-\x7F]+' => 'USERNAME_ASCII');
+
+	set_config('allow_name_chars', $config['allow_name_chars']);
+
 	// sorting thang
 	if ($map_dbms === 'mysql_41')
 	{
diff --git a/phpBB/install/schemas/schema_data.sql b/phpBB/install/schemas/schema_data.sql
index 597d37d269..e8f3bc8e07 100644
--- a/phpBB/install/schemas/schema_data.sql
+++ b/phpBB/install/schemas/schema_data.sql
@@ -18,7 +18,7 @@ INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_bookmarks',
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_emailreuse', '0');
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_forum_notify', '1');
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_mass_pm', '1');
-INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_name_chars', '.*');
+INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_name_chars', 'USERNAME_CHARS_ANY');
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_namechange', '0');
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_nocensors', '0');
 INSERT INTO phpbb_config (config_name, config_value) VALUES ('allow_pm_attach', '0');