User frold experienced a “502 Bad Gateway” error after updating their Discourse site from 2.2 beta2 to the latest release. The update process appeared to complete successfully, but the site was inaccessible. After attempting a cleanup with ./launcher cleanup and researching the issue, frold tried disabling all plugins except the Docker Manager. Eventually, frold discovered that one of their plugins was incompatible with the latest release, and after commenting it out, their site was back online. The problematic plugin is still unknown, and frold is now investigating which one caused the issue.