update dependencies , gradle, miniSdkVersion

build.gradle

@@ -3,9 +3,10 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:3.1.3'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -15,6 +16,7 @@ buildscript {
 allprojects {
     repositories {
         jcenter()
+        google()
     }
 }
 
@@ -23,9 +25,8 @@ task clean(type: Delete) {
 }
 
 ext {
-    buildToolsVersion = '25.0.2'
-    compileSdkVersion = 25
-    minSdkVersion = 9
-    targetSdkVersion = 25
-    supportLibraryVersion = '25.3.1'
+    compileSdkVersion = 27
+    minSdkVersion = 14
+    targetSdkVersion = 27
+    supportLibraryVersion = '27.1.1'
 }