diff -r 1c3c7d73c5a6 -r 19e43b7a969d mod_register_web/mod_register_web.lua
--- a/mod_register_web/mod_register_web.lua	Fri Nov 01 17:15:29 2019 +0100
+++ b/mod_register_web/mod_register_web.lua	Fri Nov 01 23:21:50 2019 +0100
@@ -129,7 +129,7 @@
 	local jid = nil;
 	form.username, form.password, form.confirm_password = nil, nil, nil;
 
-	local prepped_username = nodeprep(username);
+	local prepped_username = nodeprep(username, true);
 	if not prepped_username then
 		return nil, "Username contains forbidden characters";
 	end