I am using the endpoint described here to try to update a user with a long user name. When I do, even if I use a one character long name, I get a 400 error and the message "Invalid Developer User name <>" and the <> contains the old user name, not the new one I'm trying to change it to. Seems like this user is now stuck.
On a related note, what are the length restrictions on username/first name/last name?
Thanks!