rm /etc/apt/sources.list.d/omv-extras-org-kralizec.list
touch /etc/apt/sources.list.d/omv-extras-org-stoneburner.list
cd /etc/apt/sources.list.d
nano omv-extras-org-stoneburner.list
Put in this content and save the file:
Then:
apt-get update
apt-get upgrade