Only the latest version (master branch) would be supported/recommended.
For typos or small problems (such as broken pages), add an issue to Github describing it.
For significant security problems (arbitrary code execution, password hijacking, etc), EMail admin@datadeer.net describing the problem, and possibly with an example. I'll respond and fix the problem likely within a day. Also, anyone who sends in a significant security problem will be added to the website's "Thanks" page.
Intentionally hacking/attacking/DDossing DataDeer.net may be punishible by law, and as such, don't do it! Feel free to spin up your own clone using the tips in "README.md". If you do find a security problem, though, please let me know!