Cumulus Linux 3.4.0 and later releases replace Quagga with FRRouting (FRR) as the routing suite for the operating system.
If you are upgrading to Cumulus Linux 3.4.0 or later from a release earlier than version 3.4.0 using
apt-get upgrade, you need to follow the upgrade steps in the Cumulus Linux user guide.
However, if you are performing a full installation of Cumulus Linux 3.4.0 or later from a disk image, it already contains FRR instead of Quagga, so you don't need to upgrade anything. However, if you are using any automation tools to configure your network and are installing a new Cumulus Linux image, make sure your automation tools refer to FRR and not to Quagga.