Hidden Field Issue

Before upgrading to 2.0, I had a hidden field in registration.
Now it does not work, I just paste that code:

https://docs.ultimatemember.com/article/128-add-a-hidden-field-to-your-register-form

I paste it to the Google Re-captcha extension:
Includes -> Core -> Actions -> um-recaptcha-form.php
?
Previously it worked, now I see in the source of the page a hidden field, but the record is not added to the database as before ??

Do I do something wrong? Should I paste this code elsewhere?
Or maybe there is a new code? I am asking for help, please.

I also try this code, I found it in other file, but still doesn’t work:

	add_action('um_after_register_fields', 'add_a_hidden_field_to_register', 500);
	
	function add_a_hidden_field_to_register( $args ) {
		session_start();
		if (isset($_GET["ref"])) {
			$REF = $_GET["ref"]; 
			$_SESSION['Referer'] = $REF;
		} else {
			if (isset($_SESSION['Referer'])) {
				$REF = $_SESSION['Referer'];	
			} else {
				$REF = '';	
			};
		}; 
		 echo '<input type="hidden" id="ref" value="'.$REF.'" />';	
	};

I can pay for solving the problem.
Greetings.