Status-4-evar is a third-party Extension just like the vast majority of Extensions being hosted at addons.mozilla.org

Firefox 34.0 is a old vulnerable Release from December 1, 2014.

Doesn't Firefox 38 (esr) work? That version at least gets security updates and is supported in the current status-4-evar release. Using an old Firefox 34 version with disclosed security flaws is highly discouraged.

You can also try to find other download extensions the work with the current release.

Older versions here:

• https://addons.mozilla.org/en-US/firefox/addon/status-4-evar/versions/