diff --git a/build.gradle b/build.gradle
index 88ecdbf..6834374 100644
--- a/build.gradle
+++ b/build.gradle
@@ -28,7 +28,7 @@ dependencies {
     testImplementation 'junit:junit:4.12'
 
     // Spark framework
-    implementation 'com.sparkjava:spark-core:2.8.0'
+    implementation 'com.sparkjava:spark-core:2.9.1'
  
     // Nexmo client library
     implementation 'com.nexmo:client:4.4.0'