Magento 1 to OpenMage LTS Upgrade

We are seeking a skilled freelancer to upgrade our existing Magento 1 website to OpenMage LTS. We have an existing Magento 1 website with a custom dimensional-shipping extension. The extension already calculates the number of boxes, package dimensions and package weights. We need a senior Magento 1/OpenMage developer to perform an initial paid code review. The immediate goal is to determine how to: Upgrade the site to the latest stable OpenMage LTS release. Preserve the existing dimensional box-packing logic. Replace the obsolete FedEx, UPS and USPS rate connections with their current REST APIs and authentication. Continue returning our negotiated carrier rates at checkout.