diff --git a/downloader_library/build.gradle b/downloader_library/build.gradle
index 073e9da..aaf364f 100644
--- a/downloader_library/build.gradle
+++ b/downloader_library/build.gradle
@@ -4,11 +4,11 @@ apply plugin: 'com.github.dcendents.android-maven'
 group='com.github.bolein'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     defaultConfig {
         minSdkVersion 14
-        targetSdkVersion 27
+        targetSdkVersion 28
         consumerProguardFiles 'proguard-rules.pro'
     }
 }
@@ -36,5 +36,5 @@ artifacts {
 
 dependencies {
     api 'com.github.bolein:better-licensing:1.5.0'
-    implementation 'com.android.support:support-v4:27.0.2'
+    implementation 'com.android.support:support-v4:28.0.0'
 }
diff --git a/zip_file/build.gradle b/zip_file/build.gradle
index 71cb3d7..03a1203 100644
--- a/zip_file/build.gradle
+++ b/zip_file/build.gradle
@@ -4,11 +4,11 @@ apply plugin: 'com.github.dcendents.android-maven'
 group='com.github.bolein'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     defaultConfig {
         minSdkVersion 9
-        targetSdkVersion 27
+        targetSdkVersion 28
     }
     buildTypes {
         release {