diff --git a/build.gradle b/build.gradle
index 3b61f16..fd516ef 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,14 +1,15 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.3.31'
+    ext.kotlin_version = '1.3.21'
     repositories {
         google()
         jcenter()
-        
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.0'
+        classpath 'com.android.tools.build:gradle:3.4.2'
+        classpath 'me.tatarka:gradle-retrolambda:3.7.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.61"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -17,9 +18,12 @@
 
 allprojects {
     repositories {
+        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
+        maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter' }
+        maven { url 'https://maven.google.com' }
         google()
         jcenter()
-        
+        mavenCentral()
     }
 }