diff --git a/app/build.gradle b/app/build.gradle
index 62fe87b..60b456b 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 25
-    buildToolsVersion "25.0.2"
+    compileSdkVersion 26
+    buildToolsVersion "26.0.2"
 
     defaultConfig {
         applicationId "com.rxjava2.android.samples"
         minSdkVersion 16
-        targetSdkVersion 25
+        targetSdkVersion 26
         versionCode 1
         versionName "1.0"
     }
@@ -22,9 +22,9 @@ android {
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     testCompile 'junit:junit:4.12'
-    compile 'com.android.support:appcompat-v7:25.1.0'
-    compile 'com.android.support:recyclerview-v7:25.1.0'
-    compile 'io.reactivex.rxjava2:rxjava:2.1.1'
+    compile 'com.android.support:appcompat-v7:26.1.0'
+    compile 'com.android.support:recyclerview-v7:26.1.0'
+    compile 'io.reactivex.rxjava2:rxjava:2.1.5'
     compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
     compile 'com.amitshekhar.android:rx2-android-networking:1.0.0'
 }
diff --git a/app/src/main/java/com/rxjava2/android/samples/ui/operators/MapExampleActivity.java b/app/src/main/java/com/rxjava2/android/samples/ui/operators/MapExampleActivity.java
index ccc6ace..9e27deb 100644
--- a/app/src/main/java/com/rxjava2/android/samples/ui/operators/MapExampleActivity.java
+++ b/app/src/main/java/com/rxjava2/android/samples/ui/operators/MapExampleActivity.java
@@ -13,6 +13,7 @@
 import com.rxjava2.android.samples.utils.AppConstant;
 import com.rxjava2.android.samples.utils.Utils;
 
+import java.security.AlgorithmParameters;
 import java.util.List;
 
 import io.reactivex.Observable;
@@ -64,6 +65,7 @@ private void doSomeWork() {
 
                     @Override
                     public List<User> apply(List<ApiUser> apiUsers) throws Exception {
+                        Log.i(TAG, "map");
                         return Utils.convertApiUserListToUserList(apiUsers);
                     }
                 })
@@ -75,7 +77,9 @@ private Observable<List<ApiUser>> getObservable() {
             @Override
             public void subscribe(ObservableEmitter<List<ApiUser>> e) throws Exception {
                 if (!e.isDisposed()) {
+                    Log.i(TAG, "being next");
                     e.onNext(Utils.getApiUserList());
+                    Log.i(TAG, "end next");
                     e.onComplete();
                 }
             }
diff --git a/build.gradle b/build.gradle
index 74b2ab0..f93d608 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,9 +3,10 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:3.0.0'
 
         // 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()
     }
 }
 
diff --git a/gradle.properties b/gradle.properties
index 1f8fad9..f392872 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -13,5 +13,5 @@
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
 #Fri Jan 06 16:06:01 CST 2017
-systemProp.http.proxyHost=127.0.0.1
-systemProp.http.proxyPort=1086
+#systemProp.http.proxyHost=127.0.0.1
+#systemProp.http.proxyPort=1086
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index ddbfadd..8b89e22 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/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-3.5-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip