customfields block inputs (custom fields)

[JesusSuarz]

I hope someone has knowledge about this ..

I find very little information about it. I hope someone helps me.

I am trying to prevent users from being able to change some fields in their profile.

I found the following function:

https://developers.whmcs.com/hooks-reference/everything-else/#customfieldsave

<?php

add_hook('CustomFieldSave', 1, function($vars) {
    return array('value' => 'overridden value',);
});

this prevents any field from being editable,

however, how can I select a specific field?

img: 

someone posted an idea in 2019.

however it doesn't work, because fieldid and relid return NULL from $vars

any idea?

I just need to select the fields that I want to prevent from being edited.