If you use the addon the code is not necessary. Besides a lot of changes is made in the myCRED plugin versions, we're not sure if the old version of the addon works fine with the new version of the myCRED plugin. So we don't support the old versions of the wpDiscuz plugins and addons. 

In my main site i have 5.3.4 ver of your plugin. Does this plugin require this code, or i can remove it without problem? 

The code is not supported anymore. You should remove it. 

I have put this code in my function.php , maybe the problem comes from it ?

 
////////////////////////////////////////////////////////////////////////

// MyCred User Ranks and Badges Integration ////////////////////////////

////////////////////////////////////////////////////////////////////////

add_filter('wpdiscuz_after_label', 'wpdiscuz_mc_after_label_html', 110, 2);

function wpdiscuz_mc_after_label_html($afterLabelHtml, $comment) {

if ($comment->user_id) {

if (function_exists('mycred_get_users_rank')) { //User Rank

$afterLabelHtml .= mycred_get_users_rank($comment->user_id, 'logo', 'post-thumbnail', array('class' => 'mycred-rank'));

}

if (function_exists('mycred_get_users_badges')) { //User Badges

$users_badges = mycred_get_users_badges($comment->user_id);

if (!empty($users_badges)) {

foreach ($users_badges as $badge_id => $level) {

$imageKey = ( $level > 0 ) ? 'level_image' . $level : 'main_image';

$afterLabelHtml .= '<img src="' . get_post_meta($badge_id, $imageKey, true) . '" width="22" height="22" class="mycred-badge earned" alt="' . get_the_title($badge_id) . '" title="' . get_the_title($badge_id) . '" />';

}

}

} 

}

return $afterLabelHtml;

} 

In the active plugin list, we don't see the wpDiscuz - myCRED Integration addon installed. 

Here you said that you have the addon installed on your website.

You can scroll down and you will see this - https://prnt.sc/xtizxt

This broken image is Badge i've added in mycred pluggin. I've viewing my page with Chrome and Firefox. If i open this page with Opera, everything it's OK!  I'm using only wpdiscuz and mycred plugin. From what i know, this broken badge should not be there. It should be hided, because i'm not using your wpdiscuz mycred extension. If i disable your plugin and using wordpress default comment system, it's alright, no broken image for badge. So i belive this is some sort of conflict. 

I have only those plugins installed - https://prnt.sc/xmehi1

we don't see any badges/ranks in the link you've provided.