diff --git a/bottom_sheet/android/build.gradle b/bottom_sheet/android/build.gradle
index 59baba0..6446aaf 100644
--- a/bottom_sheet/android/build.gradle
+++ b/bottom_sheet/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/dropdown_button/android/android/build.gradle b/dropdown_button/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/dropdown_button/android/android/build.gradle
+++ b/dropdown_button/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/dropdown_button/android/build.gradle b/dropdown_button/android/build.gradle
index ea78cdf..5160cdd 100644
--- a/dropdown_button/android/build.gradle
+++ b/dropdown_button/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/dropdown_button/android/gradle/wrapper/gradle-wrapper.properties b/dropdown_button/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/dropdown_button/android/gradle/wrapper/gradle-wrapper.properties
+++ b/dropdown_button/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/enabling_splash_screen/android/android/build.gradle b/enabling_splash_screen/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/enabling_splash_screen/android/android/build.gradle
+++ b/enabling_splash_screen/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/enabling_splash_screen/android/build.gradle b/enabling_splash_screen/android/build.gradle
index 11e9518..8bd9635 100644
--- a/enabling_splash_screen/android/build.gradle
+++ b/enabling_splash_screen/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/enabling_splash_screen/android/gradle/wrapper/gradle-wrapper.properties b/enabling_splash_screen/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/enabling_splash_screen/android/gradle/wrapper/gradle-wrapper.properties
+++ b/enabling_splash_screen/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/expense_planner/android/android/build.gradle b/expense_planner/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/expense_planner/android/android/build.gradle
+++ b/expense_planner/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/expense_planner/android/build.gradle b/expense_planner/android/build.gradle
index 7909519..24ba542 100644
--- a/expense_planner/android/build.gradle
+++ b/expense_planner/android/build.gradle
@@ -2,11 +2,11 @@ buildscript {
     ext.kotlin_version = '1.4.0'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/expense_planner/android/gradle/wrapper/gradle-wrapper.properties b/expense_planner/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/expense_planner/android/gradle/wrapper/gradle-wrapper.properties
+++ b/expense_planner/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/google_signin/android/android/build.gradle b/google_signin/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/google_signin/android/android/build.gradle
+++ b/google_signin/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/google_signin/android/build.gradle b/google_signin/android/build.gradle
index 1d7e3f6..42118a3 100644
--- a/google_signin/android/build.gradle
+++ b/google_signin/android/build.gradle
@@ -1,11 +1,11 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath 'com.google.gms:google-services:4.0.1'
     }
 }
@@ -13,7 +13,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/google_signin/android/gradle/wrapper/gradle-wrapper.properties b/google_signin/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/google_signin/android/gradle/wrapper/gradle-wrapper.properties
+++ b/google_signin/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/grid_layout/android/android/build.gradle b/grid_layout/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/grid_layout/android/android/build.gradle
+++ b/grid_layout/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/grid_layout/android/build.gradle b/grid_layout/android/build.gradle
index ea78cdf..5160cdd 100644
--- a/grid_layout/android/build.gradle
+++ b/grid_layout/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/grid_layout/android/gradle/wrapper/gradle-wrapper.properties b/grid_layout/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/grid_layout/android/gradle/wrapper/gradle-wrapper.properties
+++ b/grid_layout/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/handling_routes/android/android/build.gradle b/handling_routes/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/handling_routes/android/android/build.gradle
+++ b/handling_routes/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/handling_routes/android/build.gradle b/handling_routes/android/build.gradle
index 11e9518..8bd9635 100644
--- a/handling_routes/android/build.gradle
+++ b/handling_routes/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/handling_routes/android/gradle/wrapper/gradle-wrapper.properties b/handling_routes/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/handling_routes/android/gradle/wrapper/gradle-wrapper.properties
+++ b/handling_routes/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/image_from_network/android/android/build.gradle b/image_from_network/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/image_from_network/android/android/build.gradle
+++ b/image_from_network/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/image_from_network/android/build.gradle b/image_from_network/android/build.gradle
index ea78cdf..5160cdd 100644
--- a/image_from_network/android/build.gradle
+++ b/image_from_network/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/image_from_network/android/gradle/wrapper/gradle-wrapper.properties b/image_from_network/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/image_from_network/android/gradle/wrapper/gradle-wrapper.properties
+++ b/image_from_network/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/infinite_list/android/android/build.gradle b/infinite_list/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/infinite_list/android/android/build.gradle
+++ b/infinite_list/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/infinite_list/android/build.gradle b/infinite_list/android/build.gradle
index ea78cdf..5160cdd 100644
--- a/infinite_list/android/build.gradle
+++ b/infinite_list/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/infinite_list/android/gradle/wrapper/gradle-wrapper.properties b/infinite_list/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/infinite_list/android/gradle/wrapper/gradle-wrapper.properties
+++ b/infinite_list/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/load_local_image/android/android/build.gradle b/load_local_image/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/load_local_image/android/android/build.gradle
+++ b/load_local_image/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/load_local_image/android/build.gradle b/load_local_image/android/build.gradle
index d3ad18f..095b468 100644
--- a/load_local_image/android/build.gradle
+++ b/load_local_image/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
        google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/load_local_image/android/gradle/wrapper/gradle-wrapper.properties b/load_local_image/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/load_local_image/android/gradle/wrapper/gradle-wrapper.properties
+++ b/load_local_image/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/load_local_json/android/android/build.gradle b/load_local_json/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/load_local_json/android/android/build.gradle
+++ b/load_local_json/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/load_local_json/android/build.gradle b/load_local_json/android/build.gradle
index 11e9518..8bd9635 100644
--- a/load_local_json/android/build.gradle
+++ b/load_local_json/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/load_local_json/android/gradle/wrapper/gradle-wrapper.properties b/load_local_json/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/load_local_json/android/gradle/wrapper/gradle-wrapper.properties
+++ b/load_local_json/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/navigation_drawer/android/android/build.gradle b/navigation_drawer/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/navigation_drawer/android/android/build.gradle
+++ b/navigation_drawer/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/navigation_drawer/android/build.gradle b/navigation_drawer/android/build.gradle
index 11e9518..8bd9635 100644
--- a/navigation_drawer/android/build.gradle
+++ b/navigation_drawer/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/navigation_drawer/android/gradle/wrapper/gradle-wrapper.properties b/navigation_drawer/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/navigation_drawer/android/gradle/wrapper/gradle-wrapper.properties
+++ b/navigation_drawer/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/persist_key_value/android/android/build.gradle b/persist_key_value/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/persist_key_value/android/android/build.gradle
+++ b/persist_key_value/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/persist_key_value/android/build.gradle b/persist_key_value/android/build.gradle
index 7909519..24ba542 100644
--- a/persist_key_value/android/build.gradle
+++ b/persist_key_value/android/build.gradle
@@ -2,11 +2,11 @@ buildscript {
     ext.kotlin_version = '1.4.0'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/persist_key_value/android/gradle/wrapper/gradle-wrapper.properties b/persist_key_value/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/persist_key_value/android/gradle/wrapper/gradle-wrapper.properties
+++ b/persist_key_value/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/simple_material_app/android/android/build.gradle b/simple_material_app/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/simple_material_app/android/android/build.gradle
+++ b/simple_material_app/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/simple_material_app/android/build.gradle b/simple_material_app/android/build.gradle
index 11e9518..8bd9635 100644
--- a/simple_material_app/android/build.gradle
+++ b/simple_material_app/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/simple_material_app/android/gradle/wrapper/gradle-wrapper.properties b/simple_material_app/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/simple_material_app/android/gradle/wrapper/gradle-wrapper.properties
+++ b/simple_material_app/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/stateful_widget/android/android/build.gradle b/stateful_widget/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/stateful_widget/android/android/build.gradle
+++ b/stateful_widget/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/stateful_widget/android/build.gradle b/stateful_widget/android/build.gradle
index 11e9518..8bd9635 100644
--- a/stateful_widget/android/build.gradle
+++ b/stateful_widget/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/stateful_widget/android/gradle/wrapper/gradle-wrapper.properties b/stateful_widget/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/stateful_widget/android/gradle/wrapper/gradle-wrapper.properties
+++ b/stateful_widget/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/stateless_widgets/android/android/build.gradle b/stateless_widgets/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/stateless_widgets/android/android/build.gradle
+++ b/stateless_widgets/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/stateless_widgets/android/build.gradle b/stateless_widgets/android/build.gradle
index 11e9518..8bd9635 100644
--- a/stateless_widgets/android/build.gradle
+++ b/stateless_widgets/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/stateless_widgets/android/gradle/wrapper/gradle-wrapper.properties b/stateless_widgets/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/stateless_widgets/android/gradle/wrapper/gradle-wrapper.properties
+++ b/stateless_widgets/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/tip_calculator/android/android/build.gradle b/tip_calculator/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/tip_calculator/android/android/build.gradle
+++ b/tip_calculator/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/tip_calculator/android/build.gradle b/tip_calculator/android/build.gradle
index 11e9518..8bd9635 100644
--- a/tip_calculator/android/build.gradle
+++ b/tip_calculator/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/tip_calculator/android/gradle/wrapper/gradle-wrapper.properties b/tip_calculator/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/tip_calculator/android/gradle/wrapper/gradle-wrapper.properties
+++ b/tip_calculator/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/unit_testing/android/build.gradle b/unit_testing/android/build.gradle
index 59baba0..6446aaf 100644
--- a/unit_testing/android/build.gradle
+++ b/unit_testing/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/update_gradle_wrapper.sh b/update_gradle_wrapper.sh
index c21b326..fc8195b 100755
--- a/update_gradle_wrapper.sh
+++ b/update_gradle_wrapper.sh
@@ -33,7 +33,7 @@ do
 
 		# Run command inside the sub-directory i.e Gradle project
 		./gradlew clean | egrep 'FAILED|WARNING' 
-		./gradlew wrapper --gradle-version $version --distribution-type all | grep "FAILED"
+		./gradlew wrapper --gradle-version $version --distribution-type bin | grep "FAILED"
 
 		# Print the name of the sub directory when done
 		echo "$DIR" | awk -F'/' '{print $2}' | xargs -I{} echo "      ↪️  {} ✔️"
diff --git a/using_alert_dialog/android/android/build.gradle b/using_alert_dialog/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_alert_dialog/android/android/build.gradle
+++ b/using_alert_dialog/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_alert_dialog/android/build.gradle b/using_alert_dialog/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_alert_dialog/android/build.gradle
+++ b/using_alert_dialog/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_alert_dialog/android/gradle/wrapper/gradle-wrapper.properties b/using_alert_dialog/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_alert_dialog/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_alert_dialog/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_bottom_nav_bar/android/android/build.gradle b/using_bottom_nav_bar/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_bottom_nav_bar/android/android/build.gradle
+++ b/using_bottom_nav_bar/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_bottom_nav_bar/android/build.gradle b/using_bottom_nav_bar/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_bottom_nav_bar/android/build.gradle
+++ b/using_bottom_nav_bar/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_bottom_nav_bar/android/gradle/wrapper/gradle-wrapper.properties b/using_bottom_nav_bar/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_bottom_nav_bar/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_bottom_nav_bar/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_custom_fonts/android/android/build.gradle b/using_custom_fonts/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_custom_fonts/android/android/build.gradle
+++ b/using_custom_fonts/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_custom_fonts/android/build.gradle b/using_custom_fonts/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_custom_fonts/android/build.gradle
+++ b/using_custom_fonts/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_custom_fonts/android/gradle/wrapper/gradle-wrapper.properties b/using_custom_fonts/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_custom_fonts/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_custom_fonts/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_edittext/android/android/build.gradle b/using_edittext/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_edittext/android/android/build.gradle
+++ b/using_edittext/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_edittext/android/build.gradle b/using_edittext/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_edittext/android/build.gradle
+++ b/using_edittext/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_edittext/android/gradle/wrapper/gradle-wrapper.properties b/using_edittext/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_edittext/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_edittext/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_firebase_db/android/build.gradle b/using_firebase_db/android/build.gradle
index c5f710a..aa9054c 100644
--- a/using_firebase_db/android/build.gradle
+++ b/using_firebase_db/android/build.gradle
@@ -1,11 +1,11 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath 'com.google.gms:google-services:4.3.2'
     }
 }
@@ -13,7 +13,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_firebase_db/android/gradle/wrapper/gradle-wrapper.properties b/using_firebase_db/android/gradle/wrapper/gradle-wrapper.properties
index 525a336..52cb2b9 100644
--- a/using_firebase_db/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_firebase_db/android/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.6-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.2-bin.zip
diff --git a/using_gradient/android/android/build.gradle b/using_gradient/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_gradient/android/android/build.gradle
+++ b/using_gradient/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_gradient/android/build.gradle b/using_gradient/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_gradient/android/build.gradle
+++ b/using_gradient/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_gradient/android/gradle/wrapper/gradle-wrapper.properties b/using_gradient/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_gradient/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_gradient/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_http_get/android/android/build.gradle b/using_http_get/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_http_get/android/android/build.gradle
+++ b/using_http_get/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_http_get/android/build.gradle b/using_http_get/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_http_get/android/build.gradle
+++ b/using_http_get/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_http_get/android/gradle/wrapper/gradle-wrapper.properties b/using_http_get/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_http_get/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_http_get/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_interactiveviewer/android/build.gradle b/using_interactiveviewer/android/build.gradle
index ea78cdf..5160cdd 100644
--- a/using_interactiveviewer/android/build.gradle
+++ b/using_interactiveviewer/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_listview/android/android/build.gradle b/using_listview/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_listview/android/android/build.gradle
+++ b/using_listview/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_listview/android/build.gradle b/using_listview/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_listview/android/build.gradle
+++ b/using_listview/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_listview/android/gradle/wrapper/gradle-wrapper.properties b/using_listview/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_listview/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_listview/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_snackbar/android/android/build.gradle b/using_snackbar/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_snackbar/android/android/build.gradle
+++ b/using_snackbar/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_snackbar/android/build.gradle b/using_snackbar/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_snackbar/android/build.gradle
+++ b/using_snackbar/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_snackbar/android/gradle/wrapper/gradle-wrapper.properties b/using_snackbar/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_snackbar/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_snackbar/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_stepper/android/android/build.gradle b/using_stepper/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_stepper/android/android/build.gradle
+++ b/using_stepper/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_stepper/android/build.gradle b/using_stepper/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_stepper/android/build.gradle
+++ b/using_stepper/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_stepper/android/gradle/wrapper/gradle-wrapper.properties b/using_stepper/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_stepper/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_stepper/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_tabs/android/android/build.gradle b/using_tabs/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_tabs/android/android/build.gradle
+++ b/using_tabs/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_tabs/android/build.gradle b/using_tabs/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_tabs/android/build.gradle
+++ b/using_tabs/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_tabs/android/gradle/wrapper/gradle-wrapper.properties b/using_tabs/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_tabs/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_tabs/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/using_theme/android/android/build.gradle b/using_theme/android/android/build.gradle
index 59baba0..6446aaf 100644
--- a/using_theme/android/android/build.gradle
+++ b/using_theme/android/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_theme/android/build.gradle b/using_theme/android/build.gradle
index 11e9518..8bd9635 100644
--- a/using_theme/android/build.gradle
+++ b/using_theme/android/build.gradle
@@ -1,18 +1,18 @@
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/using_theme/android/gradle/wrapper/gradle-wrapper.properties b/using_theme/android/gradle/wrapper/gradle-wrapper.properties
index 80cf08e..442d913 100644
--- a/using_theme/android/gradle/wrapper/gradle-wrapper.properties
+++ b/using_theme/android/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/view_pdf_file/android/build.gradle b/view_pdf_file/android/build.gradle
index 59baba0..6446aaf 100644
--- a/view_pdf_file/android/build.gradle
+++ b/view_pdf_file/android/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.4.32'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.1'
+        classpath 'com.android.tools.build:gradle:4.1.3'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -14,7 +14,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }