Telegram Icon

Hey Stephan,
Try adding this code to the end of your functions.php file in Appearance > Editor:

// Register new icon as a theme icon
function avia_add_custom_icon($icons) {
	$icons['telegram']	 = array( 'font' =>'entypo-fontello', 'icon' => 'ue8b7');
	return $icons;
}
add_filter('avf_default_icons','avia_add_custom_icon', 10, 1);

// Add new icon as an option for social icons
function avia_add_custom_social_icon($icons) {
	$icons['Telegram'] = 'telegram';
	return $icons;
}
add_filter('avf_social_icons_options','avia_add_custom_social_icon', 10, 1);

Then add this code in the General Styling > Quick CSS field or in the WordPress > Customize > Additional CSS field:

#top #wrap_all .av-social-link-telegram:hover a {
    color: #fff;
    background-color: #add4ef;
}

That should give you this:

Best regards,
Mike