About This Hotfix
An issue has been identified in the 8.6.0 release - published on 3rd November 2022, that causes an issue with email sending when using the Google Mail Provider. Email sending fails with the following error:
Class "WHMCS\Module\Mail\SmtpOauth" not found in /path/to/whmcs/modules/mail/SmtpMail/SmtpMail.php