Shipping doesn't work at check out

[Basara]

I updated to the new cart.   But I can't upgrade just the USPS extension.

Hello.
There are two separate USPS extensions for AbanteCart: the built-in, free version that updates with AbanteCart itself, and a third-party extension available through the marketplace https://marketplace.abantecart.com/usps_integration

[abolabo]

I updated to the new cart.   But I can't upgrade just the USPS extension.

default_usps extension is a part of AbanteCart. It upgraded with core.