Hi, simply it - if any steps are required from us when we upgrade to the Plus plan?
We're not at Shopify yet, but our growth plan considers upgrading to Plus in a few months after we launch the store.
We'd like to be 100% sure it'll make no-hassle upgrading our store.
I'm personally expecting (imagine) to see an updated admin page with a new features added, maybe some new tabs, new checkout.liquid added to the templates list, etc. I wouldn't want it to be needed any store/themes redevelopment, or if any 3rd party apps may not support the Plus plan.
It's best to launch with the less plan and upgrade later. But we can accept to go with the Plus from day zero if it will save time in the future.