diff --git a/build.sbt b/build.sbt
index 7e70f907..f50fb0e6 100644
--- a/build.sbt
+++ b/build.sbt
@@ -16,7 +16,7 @@ scalacOptions ++= "-target:jvm-1.7" :: "-Xexperimental" :: Nil
 ndkJavah := Seq()
 ndkBuild := Seq()
 
-proguardVersion := "5.3"
+proguardVersion := "5.3.1"
 proguardCache := Seq()
 proguardOptions ++=
   "-keep class com.github.shadowsocks.System { *; }" ::