One-Page Checkout [Support Thread]

[lat9]

I've got this in the error logs.

PHP Warning: html_entity_decode(): charset `CHARSET' not supported, assuming utf-8 in /Users/steph/Sites/localhost/balloonmarket/includes/classes/observers/class.checkout_one_observer.php on line 732

Using PHP 7.4

Hmm, what file contains that CHARSET definition?