There are three ways to find out if you are using an Online Store 2.0 Theme.
Ask Theme DeveloperTo top
The best way is to ask them if the theme version you are using is 2.0.
You can also email Shopify Support to get you in contact with them.
Check the Shopify Theme Store
If you just downloaded your theme you can check the Shopify Theme Store to see if your theme is an Online Store 2.0 Theme.
Stores with the OS 2.0 badge in the bottom right are 2.0 Themes
Test the app in your theme and see if you have issues.
A third way to see if you have a 2.0 theme is to test a product using our app.
If you click add to cart and the required options don’t work or it doesn’t go to the cart page then you have a 2.0 Theme and need to turn on our 2.0 Theme setting for this to work.