diff --git a/build.gradle b/build.gradle
index e6d8a8515..5c767f6a1 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,12 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
         applicationId "com.topjohnwu.magisk"
         minSdkVersion 21
-        targetSdkVersion 27
+        targetSdkVersion rootProject.ext.compileSdkVersion
         versionCode 110
         versionName "5.6.3"
         javaCompileOptions {
@@ -36,20 +37,14 @@ android {
     }
 }
 
-repositories {
-    jcenter()
-    google()
-    maven { url "https://jitpack.io" }
-}
-
 dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
     implementation project(':utils')
     implementation 'com.github.topjohnwu:libsu:1.1.1'
-    implementation 'com.android.support:recyclerview-v7:27.1.0'
-    implementation 'com.android.support:cardview-v7:27.1.0'
-    implementation 'com.android.support:design:27.1.0'
-    implementation 'com.android.support:support-v4:27.1.0'
+    implementation "com.android.support:recyclerview-v7:${rootProject.ext.supportLibVersion}"
+    implementation "com.android.support:cardview-v7:${rootProject.ext.supportLibVersion}"
+    implementation "com.android.support:design:${rootProject.ext.supportLibVersion}"
+    implementation "com.android.support:support-v4:${rootProject.ext.supportLibVersion}"
     implementation 'com.jakewharton:butterknife:8.8.1'
     implementation 'com.atlassian.commonmark:commonmark:0.10.0'
     implementation 'org.kamranzafar:jtar:2.3'