Hi Admin, We Deploy theDemoHMC4.0 with Exchange 2007 & it's working fine, you have try Scale Tier- MAPI subscriber base from 1-5,000, but right now we dont have such requirment but in future might be the users incress & we have to change only hardware.Now my question is can weexclude or add new servers on like clustring or for the mailbox. & also please sujest uswhat type of hardware we need to bye for the production environement. thanks Devender

I'm not an HMC expert, but: HMC 4.5 is out now, I would build on this instead Planning Exchange hardware for HMC is not different than other enviroments, with the exception of typically more front-end heavy connections. See here