Proguard is a popular tool for building Android projects.
Using default settings, Proguard will cause a build or compile to fail if it includes recent versions of the Mixpanel Android library (>4.0.0). Luckily, the Proguard configuration can be modified to correct this issue.
Setting your Proguard configuration to work with Mixpanel
In your proguard.cfg file, add the following line:
Learning more about Proguard
For additional information such as the location of your proguard.cfg you can consult the Proguard documentation here.