Alex.Tan  To clarify, it's not firmware, it's OneFS.  Latest target code for Gen5 nodes 8.0.0.6.  OneFS 8.1.0.x is for Gen5 & Gen6 nodes (not target code yet). Is there a particular feature that you need on OneFS 8.1.0.x? Check the Isilon Uptime Info Hub for more info.  Isilon Uptime Info Hub
Our new Isilon X210 hardware will be delivered two months later.Just considering if we could upgrade the factory fw version 8.0.0.6 to new latest version? Thanks!  Alex 
Isilon X210 upgrade from 8.0.0.6 to 8.1.0.0