iazms
meireles is right regarding security and vulnerabilities. If nothing else, hopefully you have changed your SNMP community strings.
I do have one complaint about upgrades, and it is a hit and miss. Sometimes the new agent, perhaps to address a bug or compatability problem has less functionaility than an older agent.
For example, from my Proliant 6000 servers, I used to be able to see the I/O performance of the bus. After the upgrade, I could only see CPU utilization. As we all know the CPU performance can be quite modest while the I/O is red lining. Hard to tell this with CIM 2000 miles away without the I/O performance indicator.
Alas, the agent upgrade only listed the bug fixes, and new hardware and did not inform me of what I would loose.
Richard