Brief
This winter USPS company has announced that "Rate, RateV2, RateV3 and Intl Rate will be retired in May 2011, requiring all integrators to migrate to the latest versions".
 
Description
Hereby we'd like to announce a new USPS scripts update to support V4 Domestic shipping rates and V2 International shipping rates.
 
Solution
Download this archive:
http://www.viart.com/downloads/uspsv4.zip
 
Next unzip the archive and upload the files "usps_functions.php" and "usps_v4.php" into the 'shipping' folder of your shop.
 
Once this is done, please go to Settings > Orders > Shipping Methods > Edit USPS Shipping Type and change the value in 'PHP External Library' field to "./shipping/usps_v4.php" just like in the [settings.jpg] screenshot.
 
One more change: specify "Container" parameter as "VARIABLE".
 
Additionally in this archive you can find new USPS methods for Domestic shipping ('shipping_code_dom.txt') and for International shipping ('shipping_code_int.txt').
NOTE: this list is not full and for other methods you may need to consult with USPS support.
 
To add a new shipping method go to Settings > Orders > Shipping Methods > USPS V4 > Shipping Types and click 'New Shipping Type' then in the field "Shipping Code" specify the value from one of these .txt files. Please look at [shipping_type.jpg] screenshot as an example.
 
 

Thank you Vera!

What are the PARAMETER NAME and PARAMETER SOURCE values that you used to get this to work with the shipping methods you tested with? Can you post a .jpg of the FULL shipping method parameteres that works please? Using just the parameters from a V3 method don't work.

Viart, I'm VERY grateful for the new V4 interface, it appears to work very nicely. All I did was change the two settings since the new php file was included in my upgrade recently.
 
This is why I stick with Viart, in my mind, the best and most mature cart out there, with the most features.
 
Ed

Ok, let me update my earlier post: There are errors in moving from V3 to V4. My customers are seeing Global Express Guaranteed rates for Priority Mail International Service. I'm trying to go through the USPS interface definitions, but this is NOT my area of expertise.
 
Viart, please give us some help here. SHipping is critical, and you guys are ignoring the problems we're having.

Here's a post with the problem I'm having illustrated. The USPS website says this shipment is about 34.00, but the rate quote I'm getting is double that or more. I had similar order yesterday with 6 units, only 8 pounds, and the rate was over 150.00!
 
I've updated the shipping methods with the exact names given in the zip file above, verified weights of all products, etc.
 
If I'm missing something, PLEASE let me know asap.

Q1.) Does this have anything to do with "International" shipping rather than domestic?
 
Q2.) I'm not sure if this update to USPS is for v4.0+ or not, but it appears you're using 3.6?

UPDATE: I got information from Vera this morning, and changed all my "packages_number" in products to "0.1000" and the USPS V4 seems to be working as expected, I'll continue testing this morning and see how it goes. As a reasonably good programmer in PHP and other languages, I can understand how it might be easier to use a '0.1' package, but it's not exactly intuitive that that's what it took to get it working.
 
I'll assume the patch Vera pointed me to is already part of V4.0.7 of the cart software. My frustrations are running high this week, Viart has been good to assist and point out my errors.
 
=========original post ->
Q1: Apparently it is for all shipments, domestic and inter. My rates were going nuts.
 
Q2: I"m confused. Viart has a 3.6 'patch' that I'm supposed to use for USPS V4 and then alter the table structure to make the package thing a floating number so I can put a decimal in it, and I was told to use that patch for my 4.0.7 cart by Vera in an email.
 
I'm still not sure what to do. Call me an idiot if you want, but the 'retrograde' from my 4.0.7 cart back to 3.6's USPS interface does not make sense. Don't Viart include all the upgrades in each release?