Is there any upgrade instructions?
On installing this it didn't work - not getting any rates on checkout.
Put original files back and it works again

I'm upgrading to 1.5.6c - so that's whats installed on test server.

zipship config -

Enable Zip Code Method
True

Calculation Method
Weight

Tax Class
--none--

Tax Basis
Shipping

Shipping Zone
--none--

Sort Order
0

Zone 1 Zip Codes
6004,6005,6100,6101,6102,6152,6153,6151,6152A

Zone 1 Shipping Table
14:15,70:20,130:25,999:50

Zone 1 Handling Fee
0

....

(70 zones)