Hi
Could you please explain your actual issue related to BI. If you think that you need something from BI 7.4 version, we could try and give you an alternative solution.
But if your intention is just to upgrade the BI version, then you should do a recommendation to your client/business.
Its their decision to upgrade the system with the help of Basis (90%) and you (10%). The 10% is for testing the system and clearing the delta queues, kind of activities. The actual upgrade is done by Basis team
Hence please consult your business and get their approval for upgrade. Its not an easy task and it cant be done without planning. It should go step by step with proper planning.
Hope this helps
Regards
Karthik