Java Plugin 7 update 12 to 15 (click-to-play), Linux has been blocked for your protection.

Why was it blocked?
Old versions of the Java plugin are potentially insecure and unstable. All users are strongly recommended to update on our plugin check page.
Who is affected?
All users who have these versions of the plugin installed in Firefox.
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.