Xamarin.Android Proguard - Unsupported class version number 52.0

I had a problem where Proguard was removing the Google Play Services libraries from my app.

In addition to following @Jon Douglas' answer above, I had to add the following lines of text to the proguard-android.txt file found in this folder:

/(Path to your Android SDK Folder)/tools/proguard

-keep public class com.google.android.gms.* { public *; }
-dontwarn com.google.android.gms.**

Complete proguard-android.txt File

-keep public class com.google.android.gms.* { public *; }
-dontwarn com.google.android.gms.**

# This is a configuration file for ProGuard.
# http://proguard.sourceforge.net/index.html#manual/usage.html

-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-verbose

# Optimization is turned off by default. Dex does not like code run
# through the ProGuard optimize and preverify steps (and performs some
# of these optimizations on its own).
-dontoptimize
-dontpreverify
# Note that if you want to enable optimization, you cannot just
# include optimization flags in your own project configuration file;
# instead you will need to point to the
# "proguard-android-optimize.txt" file instead of this one from your
# project.properties file.

-keepattributes *Annotation*
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService

# For native methods, see http://proguard.sourceforge.net/manual/examples.html#native
-keepclasseswithmembernames class * {
    native <methods>;
}

# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
   void set*(***);
   *** get*();
}

# We want to keep methods in Activity that could be used in the XML attribute onClick
-keepclassmembers class * extends android.app.Activity {
   public void *(android.view.View);
}

# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keepclassmembers class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator CREATOR;
}

-keepclassmembers class **.R$* {
    public static <fields>;
}

# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version.  We know about them, and they are safe.
-dontwarn android.support.**

# Understand the @Keep support annotation.
-keep class android.support.annotation.Keep

-keep @android.support.annotation.Keep class * {*;}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <methods>;
}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <fields>;
}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <init>(...);
}

You need to update the default Android SDK proguard.jar with the latest version of Proguard found here:

https://sourceforge.net/projects/proguard/files/

I would recommend that you install this on the side of the default version that Android ships in android-sdk\tools\proguard. Simply rename the existing folder to something else and add the new version of proguard.

This is listed in the Xamarin.Android 7.0 release notes:

https://developer.xamarin.com/releases/android/xamarin.android_7/xamarin.android_7.0/

In which the following bug was logged as well:

https://bugzilla.xamarin.com/show_bug.cgi?id=44187

Which is coordinated with a Pull Request in the Xamarin.Android repository:

https://github.com/xamarin/xamarin-android/pull/209