升级到java 8时是否需要向proguard规则添加任何内容？

Question

从

更改我的gradle文件后

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_7
    targetCompatibility JavaVersion.VERSION_1_7
}

到

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

我在使用proguard时收到警告

Warning: there were 1 unresolved references to library class members.
     You probably need to update the library versions.
     (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedlibraryclassmember)

我是否需要添加到java 8的proguard规则中？

编辑：发现了这个问题。似乎proguard不喜欢ConccurentHashMap。将其添加到我的proguard文件中：

-dontwarn java.util.concurrent.ConcurrentHashMap