Puremessage for Exchange 4.0.3 upgrade from 4.0.2

Yes this is correct; you can just run the installer over the top of your current installation

I'm planning on doing this soon. Is there anything I should be concerned about before running this update. I was looking for documentation on the upgrade and I couldn't find anything. Is it as easy as just running the installer? Is there any configuration that needs to be done after the upgrade? I'm currently running 4.0.2.

Yes, You can start installation on top of the existing setup. NO need to change or edit anything for existing setup. Just run your new software on over existing. That's all. No need additional job...

That's what I was thinking I just wanted to confirm.

Confirmed