It looks like the CocoaPods spec file for GeoFire is out of date as it list the wrong version of Firebase/Database as a dependency. As you can see [here](https://github.com/firebase/geofire-objc/blob/master/GeoFire.podspec) (https://github.com/firebase/geofire-objc/blob/master/GeoFire.podspec), GeoFire depends on v6.0. However, [on CocoaPods/Specs for GeoFire](https://github.com/CocoaPods/Specs/blob/9543734012238c33ea018af5a4381459c13f0916/Specs/2/8/4/GeoFire/3.0.0/GeoFire.podspec.json) (https://github.com/CocoaPods/Specs/blob/9543734012238c33ea018af5a4381459c13f0916/Specs/2/8/4/GeoFire/3.0.0/GeoFire.podspec.json), v5.0 is listed as a dependency.