How can I check if my site is on PC 1.0 or PC 2.0?

Site configurations - Via UI

In UI, "Product Families" and "Charges" in the left side navigation menu under Product Catalog will indicate that the catalog is 2.0. If you don't see the Product Families and Charges on the left panel, it would indicate that the PC version is 1.0. Here are screenshots for your reference for a PC 2.0 site:

Here is a screenshot for a PC 1.0 site:

List site configurations - Via API

You can also determine the PC version of a site using API. Below are the details:

Request:

GET [https://{site}.chargebee.com/api/v2/configurations]

Response:

Attributes: