[erichurkman]

His was only ZIP Codes. USPS only publishes ZIP Code updates once monthly, if I recall right. Technically they are copyrighted by the USPS and you are supposed to obtain a reseller license to publish official ZIP Code data.

The rate of change is very low, maybe a dozen changes per month at most. It wouldn't be unreasonable, depending on the app, to keep it reasonably up to date.

[daigoba66]

You could also have the app phone home every few days asking for up-to-date data, or diffs, and storing it locally (it shouldn't be that big). Then release a new version every now and then with roll-ups.