diff --git a/build.gradle b/build.gradle
index 53722192..60b88a3c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -16,6 +16,7 @@ allprojects {
     ext.androidBuildVersionTools = "25.0.3"
     ext.gdxVersion = "1.9.6"
     ext.gwtVersion = "2.8.0"
+    ext.slf4jVersion = "1.7.25"
 
     if (JavaVersion.current().isJava8Compatible()) {
         tasks.withType(Javadoc) {
diff --git a/docs/Integration.md b/docs/Integration.md
index 29027ab1..4895e29f 100644
--- a/docs/Integration.md
+++ b/docs/Integration.md
@@ -10,7 +10,7 @@ Current version is [![Maven Central](https://img.shields.io/maven-central/v/org.
 ```groovy
 compile 'org.mapsforge:vtm:[CURRENT-VERSION]'
 compile 'org.mapsforge:vtm-themes:[CURRENT-VERSION]'
-compile 'org.slf4j:slf4j-api:1.7.21'
+compile 'org.slf4j:slf4j-api:1.7.25'
 ```
 
 ### Android
diff --git a/vtm-app/build.gradle b/vtm-app/build.gradle
index 16cc6cf8..f971f334 100644
--- a/vtm-app/build.gradle
+++ b/vtm-app/build.gradle
@@ -5,7 +5,7 @@ dependencies {
     compile project(':vtm-themes')
     compile project(':vtm-extras')
     compile 'com.noveogroup.android:android-logger:1.3.6'
-    compile 'com.squareup.okhttp3:okhttp:3.6.0'
+    compile 'com.squareup.okhttp3:okhttp:3.8.0'
 }
 
 android {
diff --git a/vtm-http/build.gradle b/vtm-http/build.gradle
index d8de1eeb..e18ad7f6 100644
--- a/vtm-http/build.gradle
+++ b/vtm-http/build.gradle
@@ -3,7 +3,7 @@ apply plugin: 'maven'
 
 dependencies {
     compile project(':vtm')
-    compile 'com.squareup.okhttp3:okhttp:3.6.0'
+    compile 'com.squareup.okhttp3:okhttp:3.8.0'
 }
 
 sourceSets {
diff --git a/vtm-ios-example/build.gradle b/vtm-ios-example/build.gradle
index b3f32a16..74c96288 100644
--- a/vtm-ios-example/build.gradle
+++ b/vtm-ios-example/build.gradle
@@ -33,7 +33,7 @@ dependencies {
     compile "com.badlogicgames.gdx:gdx-backend-robovm:$gdxVersion"
     compile "com.mobidevelop.robovm:robovm-rt:$roboVMVersion"
     compile "com.mobidevelop.robovm:robovm-cocoatouch:$roboVMVersion"
-    compile 'org.slf4j:slf4j-simple:1.7.21'
+    compile "org.slf4j:slf4j-simple:$slf4jVersion"
 }
 
 task copyVtmResources(type: Copy) {
diff --git a/vtm-playground/build.gradle b/vtm-playground/build.gradle
index 07723b75..c10074b2 100644
--- a/vtm-playground/build.gradle
+++ b/vtm-playground/build.gradle
@@ -6,7 +6,7 @@ dependencies {
     compile project(':vtm-http')
     compile project(':vtm-jeo')
     compile project(':vtm-jts')
-    compile 'org.slf4j:slf4j-simple:1.7.21'
+    compile "org.slf4j:slf4j-simple:$slf4jVersion"
 }
 
 sourceSets {
diff --git a/vtm-tests/build.gradle b/vtm-tests/build.gradle
index fccb5189..1e456d36 100644
--- a/vtm-tests/build.gradle
+++ b/vtm-tests/build.gradle
@@ -2,12 +2,12 @@ apply plugin: 'java'
 
 dependencies {
     compile project(':vtm-http')
-    compile 'com.squareup.okhttp3:okhttp:3.6.0'
-    testCompile 'com.squareup.okhttp3:mockwebserver:3.6.0'
+    compile 'com.squareup.okhttp3:okhttp:3.8.0'
+    testCompile 'com.squareup.okhttp3:mockwebserver:3.8.0'
     testCompile 'junit:junit:4.12'
     testCompile 'org.easytesting:fest-assert-core:2.0M10'
     testCompile 'org.mockito:mockito-all:1.10.19'
-    testCompile 'org.slf4j:slf4j-simple:1.7.21'
+    testCompile "org.slf4j:slf4j-simple:$slf4jVersion"
 }
 
 sourceSets {
diff --git a/vtm-web-app/build.gradle b/vtm-web-app/build.gradle
index 53972c81..b818912f 100644
--- a/vtm-web-app/build.gradle
+++ b/vtm-web-app/build.gradle
@@ -21,7 +21,7 @@ dependencies {
     providedCompile "com.badlogicgames.gdx:gdx:$gdxVersion:sources"
     providedCompile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion:sources"
     providedCompile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion"
-    providedCompile 'org.slf4j:slf4j-api:1.7.21'
+    providedCompile "org.slf4j:slf4j-api:$slf4jVersion"
     providedCompile 'ru.finam:slf4j-gwt:1.7.7.1'
 }
 
diff --git a/vtm-web-js/build.gradle b/vtm-web-js/build.gradle
index e97ebd53..3d86fca2 100644
--- a/vtm-web-js/build.gradle
+++ b/vtm-web-js/build.gradle
@@ -22,7 +22,7 @@ dependencies {
     providedCompile "com.badlogicgames.gdx:gdx:$gdxVersion:sources"
     providedCompile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion:sources"
     providedCompile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion"
-    providedCompile 'org.slf4j:slf4j-api:1.7.21'
+    providedCompile "org.slf4j:slf4j-api:$slf4jVersion"
     providedCompile 'org.timepedia.exporter:gwtexporter:2.5.1'
     providedCompile 'ru.finam:slf4j-gwt:1.7.7.1'
 }
diff --git a/vtm-web/build.gradle b/vtm-web/build.gradle
index 4d2d7239..415bca8c 100644
--- a/vtm-web/build.gradle
+++ b/vtm-web/build.gradle
@@ -21,7 +21,7 @@ dependencies {
     compile "com.badlogicgames.gdx:gdx:$gdxVersion:sources"
     compile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion:sources"
     compile "com.badlogicgames.gdx:gdx-backend-gwt:$gdxVersion"
-    compile 'org.slf4j:slf4j-api:1.7.21'
+    compile "org.slf4j:slf4j-api:$slf4jVersion"
     compile 'ru.finam:slf4j-gwt:1.7.7.1'
 }
 
diff --git a/vtm/build.gradle b/vtm/build.gradle
index f2513016..f1205bde 100644
--- a/vtm/build.gradle
+++ b/vtm/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'java'
 apply plugin: 'maven'
 
 dependencies {
-    compile 'org.slf4j:slf4j-api:1.7.21'
+    compile "org.slf4j:slf4j-api:$slf4jVersion"
     compileOnly 'com.google.code.findbugs:jsr305:3.0.1'
 }