The FieldScout Classic mobile app is the last release of FieldScout Mobile version 3. This version reformats your history files so they can be imported into the current FieldScout Mobile (version 4), which is a complete rewrite that is more feature-rich, faster, and more reliable (and still free).
FieldScout Classic should not be installed as a new app on your device - it should only be an update to your existing FieldScout Mobile version 3 or earlier.
The current version of FieldScout Mobile should be downloaded from the Google Play Store for new installs.