diff --git a/README.md b/README.md
index 8160037..016ba04 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@
 - [x] 检测并显示导入模组的有效文件数量
 - [x] bundle文件细粒度的资源修改
 - [x] rar,7z模组格式的支持
-- [ ] 模组预览图片的支持
+- [x] 模组预览图片的支持
 - [ ] 外部目录模组和自动修改监控功能（主要提供模组制作者使用）
 
 ### [使用指引](https://github.com/xausky/UnityModManager/wiki/%E4%B8%BB%E9%A1%B5)
diff --git a/app/build.gradle b/app/build.gradle
index 91dbe1d..15b0ce7 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -4,10 +4,10 @@ android {
     compileSdkVersion 27
     defaultConfig {
         applicationId "io.github.xausky.unitymodmanager"
-        minSdkVersion 17
+        minSdkVersion 15
         targetSdkVersion 27
         versionCode 220
-        versionName "2.2.0-beta4"
+        versionName "2.2.0-rc1"
         ndk{
             abiFilters "armeabi-v7a","x86"
         }
diff --git a/libva/build.gradle b/libva/build.gradle
index 4d2ed59..1edbfee 100644
--- a/libva/build.gradle
+++ b/libva/build.gradle
@@ -3,7 +3,7 @@ apply plugin: 'com.android.library'
 android {
     compileSdkVersion 27
     defaultConfig {
-        minSdkVersion 17
+        minSdkVersion 15
         targetSdkVersion 27
         versionCode 1
         versionName "1.0"