roundcubemail ver. 1.3.5 PHP problem charset not supported

[adam2016]

error.log

[01-Apr-2018 00:33:16 Europe/Warsaw] PHP Warning:  htmlspecialchars(): charset `iso-8859-2' not supported, assuming utf-8 in /home/www/public_html/program/lib/Roundcube/rcube_washtml.php on line 491

[01-Apr-2018 00:33:16 Europe/Warsaw] PHP Warning:  html_entity_decode(): charset `iso-8859-2' not supported, assuming utf-8 in /home/www/public_html/program/lib/Roundcube/rcube_utils.php on line 501

config.inc.php
$config['default_charset'] = 'UTF-8';

What should I correct ?

[alec]

What PHP version and OS? I see this for the first time. I guess you can fix this by setting default_charset in php.ini.

[adam2016]

(PHP 5.6 - CentOS)
php.ini
default_charset = "iso-8859-2"
change to
default_charset = "UTF-8"
and Voilà everything is already ok
thx Alec

BTW - roundcube this is a genius program (nice fast stable)