Many developers mirror popular plugins on GitHub. If you can find a reputable developer’s repository that archived the 6.7 build, this is a viable secondary option. Always check the commit history to ensure the code hasn't been tampered with. How to Install the Older Version

Using outdated plugins exposes your site to known vulnerabilities that developers have patched in newer releases.

Newer versions include patches for security flaws found in older builds. By running 6.7, you may be leaving a "backdoor" open on your site.