WSOD – Apparent PHP issues – latest Highend version

I’ve updated Highend, WP, and all plugins. I’m getting WSOD intermittently. I’ve found that if I change PHP version–either to later version or older version–the problem resolves, but only for a few hours (maybe a day). This happens with any extant PHP version. Checking debug.log, I see many errors stating “PHP Deprecated: Method hb_options is deprecated since Highend version 3.7. Use highend_option instead. in /home/customer/www/website/public_html/wp-content/themes/HighendWP/functions/deprecated.php on line 611”. Seeing the same type error reported with “Method hb_pagination……on line 229” I’m using a child theme. Is it out of sync with production code? How do I address this issue?