I am new to Hybris and was following the Commerce trail given in Hybris wiki. I can see that they perform "Update" under "Platform" tag. What does this operation do ?
As you have access to the hybris wiki you should check the following URL: https://wiki.hybris.com/display/release5/Initializing+and+Updating+the+hybris+Commerce+Suite
Here you will find everything about the initialize and update functionality in the hAC of hybris.