USPS Shipping Module RateV4 does not work on OC 1.4.8

Our e-commerce site began to show an error on USPS shipping calculation. The error message is

API Disabled: RateV3. The RateV3 API is no longer available. Please follow the "RateV3 to RateV4" transition guide in the announcements section at www.usps.com/webtools to migrate to the latest version or contact your software provider or shipping administrator for assistance.

I understand that 1.4.8 is pretty old, but we are afraid to update it because it has a lot of customization on template.

May I have a quote to fix the USPS shipping module?

ttanemori wrote:.................... because it has a lot of customization on template................

Need to know the list of customizations before estimating the amount of work required.

I've PM'd you!

Don't upgrade your OpenCart!

It is the USPS API that's causing this message, not OpenCart.

Get in touch with us if you'd like us to investigate - I suspect you need to upgrade the USPS extension, not the whole of OpenCart.

Thank you very much for everyone who tried to reach me.

We concluded that we are going to use UPS shipping module for domestic shipping until we finish rebuilding the new e-commerce site.

I am happy that OpenCart forum has many professional members to assist me.

Best regards,