diff --git a/app/proguard-rules.pro b/app/proguard-rules.pro
index ec0ffe67..8210c734 100644
--- a/app/proguard-rules.pro
+++ b/app/proguard-rules.pro
@@ -8,3 +8,6 @@
   <methods>;
 }
 -dontwarn com.google.protobuf.**
+
+# TODO investigate using smaller scope
+-keep class com.google.common.cache.** { *; }