diff --git a/.travis.yml b/.travis.yml
index d933861..521eb59 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,7 +6,8 @@ jdk:
 env:
   - GRADLE_VERSION=4.6
   - GRADLE_VERSION=4.7
-  - GRADLE_VERSION=4.8
+  - GRADLE_VERSION=4.8.1
+  - GRADLE_VERSION=4.9
 
 matrix:
   exclude:
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 1948b90..0d4a951 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index d2c45a4..a95009c 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.8-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists