I made the update of my server OCS 2.1 => 2.6
Linux Distribution: Ubuntu 16.04 LTS
The update was successful.
Since this update, agents in 2.4 or 2.6 do not make me go back inventories.
Here are the agent logs:
However, older agents that are older than version 2.3 work.
If you have an idea, I'm interested :)