Hello,
From my tests, all agents from version 2.3 to version 2.8.1 can post standard data to the 2.9.1 communication server without problems. I even have old agents in version 2.1.1 on Windows 2000 Servers that are working perfectly with this server version (2.9.1).
When i mean standard data i mean the inventory and ipdiscover data, not the snmp data.
- Check your agent logfile (after executing ocsinventory-agent with the --debug parameter).
- Check your server logfile (activity.log) usually located in /var/log/ocsinventory-server.
Hope this will help you to diagnose your problem(s).