How to upgrade BOBI 4.0 with Design Studio 1.5 to BOBI 4.1

Hello, colleagues,

what is a preferred way to update the BOBI 4.0 with the Design Studio 1.5 to the BOBI 4.1 with Design Studio 1.5?

Are we supposed to uninstall the DS 1.5 for BOBI 4.0, update the BOBI and install DS 1.5 for BOBI 4.1?

Or upgrade the BOBI to 4.1 release at first and then update the Design Studio 1.5?

What will happen in first case with customer data?

Thanks..