diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index cc83b0168f..1ee9c24df1 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -226,6 +226,7 @@ p a {
 		<li>[Fix] Removed extra ampersand from ACP link (Bug #13315)</li>
 		<li>[Fix] used cleaned up version of given field identification for pre-filling a new custom profile field (Bug #13319)</li>
 		<li>[Fix] Correctly convert 2.0 website profile fields. (Bug #13379)</li>
+		<li>[Fix] Fixed the "Alphanumeric" and "Alphanumeric and spacers" username selection limitations (Bug #13391)</li>
 
 	</ul>
 
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index 4feb17cac5..46ea90fa3a 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1303,12 +1303,12 @@ function validate_username($username, $allowed_username = false)
 
 		case 'USERNAME_ALPHA_ONLY':
 			$pcre = true;
-			$regex = '[A-Za-z]+';
+			$regex = '[A-Za-z0-9]+';
 		break;
 
 		case 'USERNAME_ALPHA_SPACERS':
 			$pcre = true;
-			$regex = '[A-Za-z-\]_+ ]+';
+			$regex = '[A-Za-z0-9-[\]_+ ]+';
 		break;
 
 		case 'USERNAME_LETTER_NUM':