based on the release notes on the USPS site:
https://www.usps.com/business/web-tools-apis/2014-january-webtools-release-notes.rtf
it doesn't look like any of those changes should effect eCart. But we cant be positive till we test it.
If you see any problems with USPS shipping lookup after the rerelease on the 27th, let us know and we will fix them immediately.