What settings should be specified to connect memcached (via socket) in Bitrix, for php 7.1?

Question

1C-Bitrix

I specify according to the instructions:
Create a .settings_extra.php file in the ~/public_html/bitrix directory and add the following lines to it:
<?php
return array (
'cache' => array(
'value' => array (
'type' => 'memcache ',
'memcache' => array(
'host' => '/home/first_letter of login/login/.memcached.sock', // you must specify your data in this line
'port' => '0'
),
' sid' => $_SERVER["DOCUMENT_ROOT"]."#01"
),
),
);
Create a dbconn.php file in the ~/public_html/bitrix/php_interface directory and add the following lines to it:
define("BX_CACHE_TYPE", "memcache");
define("BX_CACHE_SID", $_SERVER["DOCUMENT_ROOT"]."#01");
define("BX_MEMCACHE_HOST", "/home/login_first letter/login/.memcached.sock"); // in this line you must specify your data
define("BX_MEMCACHE_PORT", "0");

does not work, a warning is displayed -

Attention! PHP 7 does not support php_memcache and may have problems.

Answer 1

interestingly, starting from php 7.0 to php 7.2, it seems to work if you write like this:
'host' => ' unix:///home/first_letter of login/login/.memcached.sock ',
at least Bitrix does not give an error. But the question remains open - It is not clear whether memcached works at all or not.
the developer's warning is confusing: "Warning! PHP 7 does not support php_memcache and there may be problems."
What specific versions do you mean? everything from php7.0 to php7.4.7 ?
cms kernel version - 20.0.650