Merge - Migrate to 7.1

I have a website that I would like to merge into a 7.1 or migrate (which looks impossible). The issue is I have products and clients already in subscriptions, mailing lists. How is this done in a way that doesn't interfere with my service to my clients?

From what I have learned, there is no smooth way to migrate to 7.1 without being disruptive to your business unfortunately. I'd also like to switch to 7.1 but you have to completely rebuild using a new plan, cancel the old site, and then move your domain to the new site. Really frustrating. 😞

Here is an article with tips: https://support.squarespace.com/hc/en-us/articles/360038270572