Fatal error: Uncaught Error: Call to undefined function mb_convert_encoding() in /var/www/piwigo/include/emogrifier.class.php:434
Stack trace:
#0 /var/www/piwigo/include/emogrifier.class.php(411): Emogrifier->getUnifiedHtml()
#1 /var/www/piwigo/include/emogrifier.class.php(233): Emogrifier->createXmlDocument()
#2 /var/www/piwigo/include/functions_mail.inc.php(963): Emogrifier->emogrify()
#3 /var/www/piwigo/include/functions_mail.inc.php(861): move_css_to_body('<!DOCTYPE html ...')
#4 /var/www/piwigo/include/functions_mail.inc.php(473): pwg_mail(Array, Array, Array)
#5 /var/www/piwigo/admin/include/updates.class.php(221): pwg_mail_admins(Array, Array, false, true)
#6 /var/www/piwigo/include/page_tail.php(63): updates->notify_piwigo_new_versions()
#7 /var/www/piwigo/identification.php(144): include('/var/www/piwigo...')
#8 {main}
thrown in /var/www/piwigo/include/emogrifier.class.php on line 434