No previous versions will be supported. This project is not meant to be self-hosted. Doing so means you assume any risks associated. Only the latest version will be supported for security updates, which will be pushed via new versions.
Reporting security issues should be done via email ideally. I can be reached at [email protected]. Please include the repository you are reporting issues for, as well as any information regarding repro or related files (if you happen to know where the issue lies). I will work with you to identify the issues and patch them.