Re: PI system upgrade from 7.1 to 7.4 dual stack

http://scn.sap.com/community/process-orchestration/blog/2014/01/30/migration-from-double-stack-to-single-stack-integration-scenariosHi Aman,  

As hareesh mentioned above that if you are using more CCBPM scenario in your development then you need to install netweaver BPM as per the licensed provide by SAP, If you are not using BPM scenerios then you can go with SAP PI 7.4 with dual stack that is better.

Kindly go through the below blog to choose your upgradation.

Migration from Double stack to Single stack Integration Scenerio :