The application changelog is posted here: https://github.com/OpenSprinkler/OpenSprinkler-App/releases and in the latest release, 1.4.7, the location field was updated and works as follows:
Location input is no longer text based but instead opens a Google Maps overlay. When a Weather Underground API key is provided, nearby personal and airport weather stations are shown. When a selection is made, the GPS coordinates are saved (this works for PWS and ICAO codes). A search box is provided at the top of the map which allows any input, such as: street address, zip code, GPS coordinates, etc. Google also provides auto completion results for your assistance.
Just to clarify, when using the GPS coordinates: Weather Underground will resolve to the same weather station.
Update: Regarding the configuration, this is cleared on every update. Both the documentation and firmware updater tool warn of this when updating.