diff --git a/app/build.gradle b/app/build.gradle
index b1ac604..c465eaa 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -9,7 +9,7 @@ android {
 
     defaultConfig {
         applicationId "com.common.weikaiyun"
-        minSdkVersion 21
+        minSdkVersion 19
         targetSdkVersion 30
         versionCode 1
         versionName "1.0"
diff --git a/fragmentation/build.gradle b/fragmentation/build.gradle
index be7171f..f29c9c5 100644
--- a/fragmentation/build.gradle
+++ b/fragmentation/build.gradle
@@ -5,7 +5,7 @@ android {
     compileSdkVersion 30
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 19
         targetSdkVersion 30
         versionCode 1
         versionName "1.0"
diff --git a/fragmentation_swipeback/build.gradle b/fragmentation_swipeback/build.gradle
index c42586c..a8eeeb9 100644
--- a/fragmentation_swipeback/build.gradle
+++ b/fragmentation_swipeback/build.gradle
@@ -5,7 +5,7 @@ android {
     compileSdkVersion 30
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 19
         targetSdkVersion 30
         versionCode 1
         versionName "1.0"