Thanks for the reply. Actually, we updated switch firmware a few months ago, I have just checked it and we are already 4 updates behind.
If it comes to updating software, we have more of those switches working in a stack. I pulled out one switch to test DHCP snooping before deploying it to the production network. If I upgrade the test switch, I assume I have to do upgrade on the whole stack? Otherwise, can I downgrade my test switch if I decide not to go ahead with upgrading stack in the production network?