As @PaulNewton mentioned above, you are unable to downgrade and would need to use a different theme. Shopify has 9 free vintage themes you can choose from below:
In regards to the Bold Subscriptions app, they recently launched a second version of the app, I would highly suggest getting in contact with the developers directly to see if this latest version is supported on OS2.0 themes:
Otherwise, how is the rest of your store coming along? While you’re working on your website, I highly recommend checking out Shopify Learn. We have a course on website design that goes through how to set up a website that suits your brand well. There are other courses too, from analyzing your data to marketing to your target customers.
If you have any questions, feel free to let us know!
Thank you! I reached out to Bold Subscriptions and unfortunately they said they don’t support this, even with v2. I’m so surprised there’s no ability for me to use a buy button and subscription and hope that feature is enabled soon!
While the ability to use a buy button and subscription app is limited to Bold Subscriptions and vintage themes, I completely understand the need for this in tailoring the checkout of your website, so I’m glad to submit this feedback to our development team. It’s not an immediate and guaranteed solution, however, we do consider your suggestions when we release updates on our platform. Updates will be published on our Shopify Changelog page below: