As of today user might be running powerkvm-18.104.22.168-32 on Power8 server. User might want to update powerkvm to latest releases as PowerKVM 2.1.1 out.
1) Make sure to switch off guests
Either from a Management layer ( kimchi/CMO/Openstack..etc) or just use virsh destroy
2) Copy latest powerkvm iso (2.1.1) or latest to powerkvm machine.
3) Run Below
ibm-update-system –upgrade –iso-path=
4) Update all packages and reboot.
Upgrading virtual machines is as same as any other Linux Distribution upgrade ( yum or zypper )