The PC 2.0 (Product Catalog 2.0) migration to the live site happens with a minute of downtime. It is highly recommended that this live migration be done during your non-production hours.

Nevertheless, there is a workaround to avoid this one-minute downtime by deploying the below code. 

Site Configuration API helps you to identify whether the site is in PC1.0 or PC2.0

We suggest you to deploy API changes to the live site using an ‘if’ condition

If the site is in PC1.0, old API (PC1.0) to be called
If the site is in PC2.0, new API (PC2.0) to be called

For example:
Live site switches to PC2.0
Merchant calls Site Configuration API - it will return v2
New PC2.0 API calls will come into effect
No downtime

If there are any issues after the live upgrade, we can revert to PC1.0 (less than a min back-end action). Again, no downtime, if Site Configuration API is used.

For example:
Live site switches to PC2.0
An issue identified - revert to PC1.0
Merchant calls Site Configuration API - it will return v1
Old PC1.0 API calls will come into effect
No downtime