osTicket v1.9.15 Maintenance release for osTicket v1.9 === Enhancements * Introduce the concept of Trusted Proxies and Local Networks (8ca6bc30) === Performance and Security * Fix memory leak when applying `Use Reply-To Email` ticket filter * action (8ca6bc30) * XSS: Sanitize and validate HTTP_X_FORWARDED_FOR header (#3439, * b794c599) * XSS: Encode html chars on help desk title/name (#3439, a57de770)