diff --git a/app b/app
index 0c782edf2..52d478df1 160000
--- a/app
+++ b/app
@@ -1 +1 @@
-Subproject commit 0c782edf2114621056093406d808d03bdfed1a9f
+Subproject commit 52d478df1a687070680f057308f3d66bff9f1623
diff --git a/build.gradle b/build.gradle
index e6b32bc78..76a599ae9 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,9 +19,16 @@ allprojects {
     repositories {
         google()
         jcenter()
+        maven { url "https://jitpack.io" }
     }
 }
 
+ext {
+    compileSdkVersion = 27
+    buildToolsVersion = "27.0.3"
+    supportLibVersion = "27.1.0"
+}
+
 task clean(type: Delete) {
     delete rootProject.buildDir
 }
diff --git a/native/build.gradle b/native/build.gradle
index 351873f4f..496845318 100644
--- a/native/build.gradle
+++ b/native/build.gradle
@@ -1,7 +1,8 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     externalNativeBuild {
         ndkBuild {
diff --git a/snet/build.gradle b/snet/build.gradle
index b93107f57..9dcd17c98 100644
--- a/snet/build.gradle
+++ b/snet/build.gradle
@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 27
-    buildToolsVersion "27.0.3"
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
         applicationId "com.topjohnwu.snet"
         minSdkVersion 21
-        targetSdkVersion 27
+        targetSdkVersion rootProject.ext.compileSdkVersion
         versionCode 1
         versionName "1.0"
     }
@@ -20,10 +20,6 @@ android {
     }
 }
 
-repositories {
-    google()
-}
-
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'com.google.android.gms:play-services-safetynet:7.0.0'  /* The oldest version */