diff --git a/.gitignore b/.gitignore
index c6cbe562..054a0020 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,8 @@
 /local.properties
 /.idea/workspace.xml
 /.idea/libraries
+/.idea/encodings.xml
+/.idea/misc.xml
 .DS_Store
 /build
 /captures
diff --git a/build.gradle b/build.gradle
index 88d246d4..a7c6c440 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,10 +1,14 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
+apply from: 'dependencies.gradle'
+
 buildscript {
+    apply from: 'dependencies.gradle'
+
     repositories {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.2.3'
+        classpath gradlePlugins.androidTools
     }
 }
 
diff --git a/dependencies.gradle b/dependencies.gradle
new file mode 100644
index 00000000..26c0e40a
--- /dev/null
+++ b/dependencies.gradle
@@ -0,0 +1,18 @@
+ext.versions = [
+        minSdk               : 14,
+        targetSdk            : 22,
+        compileSdk           : 22,
+
+        buildTools           : "23.0.3",
+        androidTools         : "2.2.0",
+
+        androidSupport       : "18.0.0",
+]
+
+ext.gradlePlugins = [
+        androidTools : "com.android.tools.build:gradle:$versions.androidTools"
+]
+
+ext.androidSupport = [
+        support : "com.android.support:support-v4:$versions.androidSupport"
+]
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0c71e760..eaba3011 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-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-all.zip
diff --git a/library/build.gradle b/library/build.gradle
index d9c664d2..c0fac0ff 100644
--- a/library/build.gradle
+++ b/library/build.gradle
@@ -1,12 +1,12 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 19
-    buildToolsVersion "23.0.3"
+    compileSdkVersion versions.compileSdk
+    buildToolsVersion versions.buildTools
 
     defaultConfig {
-        minSdkVersion 7
-        targetSdkVersion 19
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
     }
 
     buildTypes {
@@ -18,5 +18,5 @@ android {
 }
 
 dependencies {
-    compile 'com.android.support:support-v4:18.0.0'
+    compile androidSupport.support
 }
diff --git a/menudrawer/build.gradle b/menudrawer/build.gradle
index 70a74c2c..1670670d 100644
--- a/menudrawer/build.gradle
+++ b/menudrawer/build.gradle
@@ -1,12 +1,12 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 19
-    buildToolsVersion "23.0.3"
+    compileSdkVersion versions.compileSdk
+    buildToolsVersion versions.buildTools
 
     defaultConfig {
-        minSdkVersion 7
-        targetSdkVersion 19
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
     }
 
     buildTypes {
diff --git a/pulltorefresh/build.gradle b/pulltorefresh/build.gradle
index 70a74c2c..1670670d 100644
--- a/pulltorefresh/build.gradle
+++ b/pulltorefresh/build.gradle
@@ -1,12 +1,12 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 19
-    buildToolsVersion "23.0.3"
+    compileSdkVersion versions.compileSdk
+    buildToolsVersion versions.buildTools
 
     defaultConfig {
-        minSdkVersion 7
-        targetSdkVersion 19
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
     }
 
     buildTypes {
diff --git a/ultrasonic/build.gradle b/ultrasonic/build.gradle
index 154952b9..5287aeb9 100644
--- a/ultrasonic/build.gradle
+++ b/ultrasonic/build.gradle
@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 19
-    buildToolsVersion "23.0.3"
+    compileSdkVersion versions.compileSdk
+    buildToolsVersion versions.buildTools
 
     defaultConfig {
         applicationId "org.moire.ultrasonic"
-        minSdkVersion 14
-        targetSdkVersion 19
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
     }
 
     buildTypes {