Export/import alert rule and alert category form PI 7.0 to PI 7.5

Hi, all!

We got a requirement to migrate from PI 7.0 (Dual-Stack) to PI 7.5 (Java single).

I have few questions about alert rule and alert category.

1. Is there a way to export them form PI 7.0 and import them into PI 7.5?

2.If no, does it mean that I have to create them in PI 7.5 manually or just alert rules are enough?

3.What is the difference between them in PI 7.0 and PI 7.5?

Thanks.

Li