What changed for USPS RateV4 Intl RateV2 Mar 7, 2014 Version K3

I would like to know what are the changes from the last USPS module, to this one...?

USPS RateV4 Intl RateV2 Mar 7, 2014 Version K3 (First-Class changes)

As of March 7, USPS changed the names of their products.
Thus, none of the First Class shipping methods will work in your store without the March 7, 2014 version K3 shipping module ...

There were various other clean up methods. So, you really do want to upgrade to it ...

You can merge your customizations into it by using something like Beyond Compare from scootersoftware.com ...

It might help you to compare your current USPS files to a clean copy of that version and comment your changes so that they stand out when you try to merge those customizations in the K3 version ...