@FredS 

Please upgrade, could be a reason for the 

https://docs.centreon.com/docs/upgrade/upgrade-from-20-10/

https://docs.centreon.com/docs/releases/lifecycle/#maintenance-table-for-centreon-versions

Hello

well, it's a big problem

I followed these instructions https://docs.centreon.com/docs/upgrade/upgrade-from-20-10/

and of course when I get to

dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
dnf install -y https://rpms.remirepo.net/enterprise/remi-release-8.rpm
sudo subscription-manager repos --enable codeready-builder-for-rhel-8-x86_64-rpms 

everything crashes logically since I'm running centos 7

so I tried several tutorials to upgrade centos 7 to centos 8 (I'm a debian user and not at all centos or redhat), and none of them work, I still end up with errors everywhere.

the best result I've had is centos8 displayed at startup, but with a kernel in rescue mode from my centos 7, and of course, behind all this, centreon was completely broken.

if you have the right tuto to upgrade the OS and centreon i'm a taker.

Thank you in advanced.