Nagios Support Forum

Hi everyone, i hope you're all fine.
First of all i'm sorry if i'm not clear, i'm not really good in english.

I'm a beginner with NagiosCore, and i actually have to install et new nagios server (with the last version). The thing is there is already a nagioscore installed (based on a 3.x version) with about 200 hosted, but i decided to restart from zero to understand how it works.
Then my question is, do I have to remove the agent of all hosts, one by one, before i have to install my "own" agent ?

Thank you in advance for your help.

If you are referring to the Agents on machines you are monitoring, no. You should be able to use the same agents with the latest version of Nagios.