Allowing other file type uploads for client documents

Hello, any help regarding this will be much appreciated.

I would like to allow for other filetypes (i.e. “mp4”) to be uploaded in the client portal document section.
I have read a similar thread posted a few years ago, and have used that to find the Document.php file in app/Models, but adding the new filetypes that I want to be allowed is not reflecting on the live installation.

That post (Attaching video files to invoices and quotes) is some years old now, so is there something that I am missing now?

I have apcu and opcache, have tried disabling those temporarily/resetting cache, no change.
Erasing local cookies/cache, running in incognito, or on other devices shows no change as well.

My addition looks like this:

        'mp4' => [
            'mime' => 'video/mp4',

Hosted on shared server, cpanel/apache with PHP 8.3


This would require changes to the frontend and backend, feel free to create an issue on GitHub to request the change.