OwnTracks initially was MQTTitude.

OwnTracks uses COCOAPODS.

Staying in the OwnTracks/ directory, launch xcode:

 % open OwnTracks.xcworkspace

Next, click on the OwnTacks project and you will see two targets, OwnTracks and OwnTracksToday. For each project, go to the General tab.

For the OwnTracks target, set the Bundle Identifier accordingly:

 com.example.OwnTracks

For the OwnTracksToday target, set the Bundle Identifier accordingly:

 com.example.OwnTracks.OwnTracksToday

For the OwnTracks project, go to the Signing and Capabilities tab and set the appropriate team. Then scroll down to App Groups, uncheck group.org.owntracks.OwnTracks, and then click on the + to create your own group, e.g.,

 group.com.example.OwnTracks

Finally, for the OwnTracksToday project, go to the Signing and Capabilities tab, set the appropriate team. Then scroll down to App Groups, uncheck group.org.owntracks.OwnTracks, and check the group you create for the OwnTracks project.

Note that most these changes will result in Xcode creating provision profiles, repairing things, etc. Please take your time and be patient!

With these steps complete, you should be able to compile and run the project.