Firefox, unlike many other applications, keeps a store of its own trusted root certificate authorities. This means that adding a new root certificate to the operating system will not work. This post runs through how to add a new root certificate to Firefox.
This post describes how you can upgrade Raspbian Jessie, version 8, to Raspbian Stretch, version 9. Raspbian Stretch was recently released and while they recommend installing from fresh you are able to upgrade the versions. Here I follow the steps of upgrading the Raspberry Pi’s in my cluster including some of the common problems that