I found a solution for the problem with characters encoding

(in my case I was using ISO-8859-1)
Go to Subs-RSS.php and find:
// Create the Post
$msg_title = $feed['html'] ? $context['feeditems'][$i]['title'] : strip_tags($context['feeditems'][$i]['title']);
$msg_body = $feed['html'] ? $context['feeditems'][$i]['description'] . "\n\n" . $context['feeditems'][$i]['link'] : strip_tags($context['feeditems'][$i]['description'] . "\n\n" . $context['feeditems'][$i]['link']);
Replace with this one or change it according to your enconding needs (this one converts to ISO-8859-1):
// Create the Post
$msg_title_ = $func['htmlspecialchars'](($feed['html'] ? $context['feeditems'][$i]['title'] : strip_tags($context['feeditems'][$i]['title'])), ENT_QUOTES);
$msg_title = iconv("UTF-8", "ISO-8859-1", $msg_title_); //// NEW added Code
$msg_body_ = $func['htmlspecialchars'](($feed['html'] ? $context['feeditems'][$i]['description'] . "\n\n" . $context['feeditems'][$i]['link'] : strip_tags($context['feeditems'][$i]['description'] . "\n\n" . $context['feeditems'][$i]['link'])), ENT_QUOTES);
$msg_body = iconv("UTF-8", "ISO-8859-1", $msg_body_); //// NEW added Code
Its working now
