Does somebody know about a clear procedure to upgrade IPCC from 3.5.4 to 5.x. I found something that telling that you can only pass from 4.5 to 5.x but in this procedure we can convert the license from 3.5 to 5.x????
I am afraid there is no positive answer to your enquiry.
At the beginning of the document you mention there is clearly written:"This chapter describes how to upgrade from CRS 4.5(x) to CRS 5.0(2). Direct upgrades from other Cisco releases are not supported."
You will need to request a new license with a valid support contract via Product Upgrade Tool and given all the installer/product changes the best approach would be to perform a clean install.