MM9 upgrade or new install

[cway]

I have a MM5.5 customer that wants MM9. Should I upgrade their store or start with a fresh install and export/import everything?
Thanks!
...

[lesliekirk]

I've been trying to get an MM4 store owner to move to MM5.5 for a couple of years now. Even have a MM5.5 dev site with a new look and feel just siting...

[gmahler5th]

I am currently running Miva engine v5.13 and in order to get the SEO features and custom category fields in my Miva store that I need, I have to upgrade...