diff --git a/EmPubLite-AndroidStudio/T10-ViewPager/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T10-ViewPager/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T10-ViewPager/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T10-ViewPager/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T11-HelpAbout/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T11-HelpAbout/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T11-HelpAbout/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T11-HelpAbout/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T12-Book/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T12-Book/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T12-Book/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T12-Book/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T13-Prefs/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T13-Prefs/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T13-Prefs/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T13-Prefs/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T14-Database/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T14-Database/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T14-Database/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T14-Database/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T15-Share/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T15-Share/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T15-Share/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T15-Share/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T16-Update/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T16-Update/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T16-Update/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T16-Update/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T17-LargeScreen/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T17-LargeScreen/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T17-LargeScreen/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T17-LargeScreen/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T2-Project/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T2-Project/EmPubLite/app/build.gradle
index aa5b0c278..420cd232c 100644
--- a/EmPubLite-AndroidStudio/T2-Project/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T2-Project/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T3-Manifest/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T3-Manifest/EmPubLite/app/build.gradle
index aa5b0c278..420cd232c 100644
--- a/EmPubLite-AndroidStudio/T3-Manifest/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T3-Manifest/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T4-Resources/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T4-Resources/EmPubLite/app/build.gradle
index aa5b0c278..420cd232c 100644
--- a/EmPubLite-AndroidStudio/T4-Resources/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T4-Resources/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T5-Layout/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T5-Layout/EmPubLite/app/build.gradle
index aa5b0c278..420cd232c 100644
--- a/EmPubLite-AndroidStudio/T5-Layout/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T5-Layout/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T6-Library/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T6-Library/EmPubLite/app/build.gradle
index 1ae898ce4..38c066820 100644
--- a/EmPubLite-AndroidStudio/T6-Library/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T6-Library/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T7-ActionBar/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T7-ActionBar/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T7-ActionBar/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T7-ActionBar/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T8-Activities/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T8-Activities/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T8-Activities/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T8-Activities/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15
diff --git a/EmPubLite-AndroidStudio/T9-Fragments/EmPubLite/app/build.gradle b/EmPubLite-AndroidStudio/T9-Fragments/EmPubLite/app/build.gradle
index 3d70c04e2..8b6cf9ac5 100644
--- a/EmPubLite-AndroidStudio/T9-Fragments/EmPubLite/app/build.gradle
+++ b/EmPubLite-AndroidStudio/T9-Fragments/EmPubLite/app/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion '26.0.2'
+    
     defaultConfig {
         applicationId "com.commonsware.empublite"
         minSdkVersion 15