diff --git a/build.gradle b/build.gradle
index 55db43f..ae9fbaf 100644
--- a/build.gradle
+++ b/build.gradle
@@ -6,7 +6,7 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.2.1'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index b9d8ccd..0b8c5eb 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip
diff --git a/libp7zip/build.gradle b/libp7zip/build.gradle
index 6656322..c87d136 100644
--- a/libp7zip/build.gradle
+++ b/libp7zip/build.gradle
@@ -9,7 +9,7 @@ android {
         versionCode 6
         versionName "1.6.0"
         ndk {
-            abiFilters 'armeabi-v7a'//, 'arm64-v8a', 'x86'
+            abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86'
         }
         externalNativeBuild {
             cmake {
diff --git a/libp7zip/src/main/cpp/CMakeLists.txt b/libp7zip/src/main/cpp/CMakeLists.txt
index 1d33394..c2ca9bb 100644
--- a/libp7zip/src/main/cpp/CMakeLists.txt
+++ b/libp7zip/src/main/cpp/CMakeLists.txt
@@ -9,6 +9,9 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -DANDROID_NDK -fexceptions -DNDEBUG -D_REENTRANT -DENV_UNIX")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DBREAK_HANDLER -DUNICODE -D_UNICODE -DUNIX_USE_WIN_FILE -fPIC")
 
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
+
 # Creates and names a library, sets it as either STATIC
 # or SHARED, and provides the relative paths to its source code.
 # You can define multiple libraries, and CMake builds it for you.