Username using numbers only.Is it possible?-Solved

Hi, I’m just done installing Nerthserver 2.8. Coming from Zentyal and Univention.
I notice that the username for domain have restriction/limitation.
If possible, we want to user our staff id as username(only numbers).
Is there any way we could do that in Nerth?
Thank you in advance for any reply or answer.

I couldn’t find a definitive answer on centos username syntax:

You could try to hack the web panel. Modify line 48 of /usr/share/nethesis/NethServer/Module/User/Modify.php:
$userNameValidator = $this->createValidator(Validate::ANYTHING)->platform('user-create');

Then, please let us know it everything still works.

Another option would be to create all user starting with the same first letter, something like:
u101
u234

Thanks filippo_carlettim
While it is possible to edit /usr/share/nethesis/NethServer/Module/User/Modify.phpm Its effect is only on User Page meaning the user can be created but it cannot join groups or shared folder.
For system wide i edit the /usr/share/nethesis/Nethgui/System/Validator.php and change the regex check for the username to accept all alphanumeric without mandatory start by alphabet.
Thank you for directing me in the correct direction.