diff --git a/app/proguard-rules.pro b/app/proguard-rules.pro
index 086512c..ebdf65e 100644
--- a/app/proguard-rules.pro
+++ b/app/proguard-rules.pro
@@ -2,5 +2,6 @@
 # fields. Proguard removes such information by default, keep it.
 -keepattributes Signature
 
+-keep class org.joda.convert.** { *; }
 # Optional. For using GSON @Expose annotation
 -keepattributes AnnotationDefault,RuntimeVisibleAnnotations
\ No newline at end of file