diff --git a/app/proguard.cfg b/app/proguard.cfg
index 09d6eeaa..139dd19f 100644
--- a/app/proguard.cfg
+++ b/app/proguard.cfg
@@ -63,8 +63,6 @@
 -dontwarn jscl.mathml.**
 -dontwarn com.google.common.**
 -dontwarn com.google.ads.**
--dontwarn com.sun.org.apache.xerces.internal.impl.dv.util.Base64
--dontwarn com.actionbarsherlock.BuildConfig
 -dontwarn com.google.android.gms.internal.**
 -dontwarn com.google.android.gms.common.internal.**
 -dontwarn com.google.android.gms.common.GooglePlayServicesUtil
@@ -73,16 +71,6 @@
 -dontwarn com.squareup.leakcanary.**
 
 -keep class org.simpleframework.xml.** { *; }
--keep class * implements org.solovyev.android.calculator.model.MathPersistenceEntity
--keep class * implements org.solovyev.android.calculator.MathEntityPersistenceContainer
-
-# Allow obfuscation of android.support.v7.internal.view.menu.**
-# to avoid problem on Samsung 4.2.2 devices with appcompat v21
-# see https://code.google.com/p/android/issues/detail?id=78377
--keep class android.support.v4.app.** { *; }
--keep interface android.support.v4.app.** { *; }
--keep class !android.support.v7.internal.view.menu.MenuBuilder, !android.support.v7.internal.view.menu.SubMenuBuilder, android.support.v7.** { *; }
--keep interface android.support.v7.** { *; }
 
 ## JAVAX UNITS
 
@@ -106,45 +94,8 @@
     public static *;
 }
 
-## ACRA
-
-# keep this around for some enums that ACRA needs
--keep class org.acra.ReportingInteractionMode {
-    *;
-}
-
--keepnames class org.acra.sender.HttpSender$** {
-    *;
-}
-
--keepnames class org.acra.ReportField {
-    *;
-}
-
-# keep this otherwise it is removed by ProGuard
--keep public class org.acra.ErrorReporter {
-    public void addCustomData(java.lang.String,java.lang.String);
-    public void putCustomData(java.lang.String,java.lang.String);
-    public void removeCustomData(java.lang.String);
-}
-
-# keep this otherwise it is removed by ProGuard
--keep public class org.acra.ErrorReporter {
-    public void handleSilentException(java.lang.Throwable);
-}
-
-## BUTTERKNIFE
-
--keep class butterknife.** { *; }
--dontwarn butterknife.internal.**
--keep class **$$ViewBinder { *; }
-
--keepclasseswithmembernames class * {
-    @butterknife.* <fields>;
-}
-
--keepclasseswithmembernames class * {
-    @butterknife.* <methods>;
+-assumenosideeffects class org.solovyev.android.plotter.Check {
+    public static *;
 }
 
 ## OTTO BUS