diff --git a/apps/sparkjava/01-hello-world/build.gradle b/apps/sparkjava/01-hello-world/build.gradle
index b1172c80..ac647c6e 100644
--- a/apps/sparkjava/01-hello-world/build.gradle
+++ b/apps/sparkjava/01-hello-world/build.gradle
@@ -11,7 +11,7 @@ mainClassName = 'sparkles.SparklesApp'
 
 dependencies {
   // 3rd party
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'org.slf4j:slf4j-api:1.7.29'
   implementation 'org.slf4j:slf4j-simple:1.7.29'
   // testing
diff --git a/apps/sparkjava/02-hello-moshi/build.gradle b/apps/sparkjava/02-hello-moshi/build.gradle
index e15b9e11..2e9ecca6 100644
--- a/apps/sparkjava/02-hello-moshi/build.gradle
+++ b/apps/sparkjava/02-hello-moshi/build.gradle
@@ -11,7 +11,7 @@ mainClassName = 'sparkles.SparklesApp'
 
 dependencies {
   // 3rd party
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'org.slf4j:slf4j-api:1.7.29'
   implementation 'org.slf4j:slf4j-simple:1.7.29'
   implementation 'com.squareup.moshi:moshi:1.9.2'
diff --git a/apps/sparkjava/03-hello-jwt/build.gradle b/apps/sparkjava/03-hello-jwt/build.gradle
index 07b78b0a..b2748320 100644
--- a/apps/sparkjava/03-hello-jwt/build.gradle
+++ b/apps/sparkjava/03-hello-jwt/build.gradle
@@ -12,7 +12,7 @@ mainClassName = 'sparkles.SparklesApp'
 dependencies {
   // 3rd party
   implementation 'com.google.guava:guava:27.0.1-jre'
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'org.slf4j:slf4j-api:1.7.29'
   implementation 'org.slf4j:slf4j-simple:1.7.29'
   implementation 'com.squareup.moshi:moshi:1.9.2'
diff --git a/apps/sparkjava/04-environment-and-logging/build.gradle b/apps/sparkjava/04-environment-and-logging/build.gradle
index 3d1e380d..5e52b8ee 100644
--- a/apps/sparkjava/04-environment-and-logging/build.gradle
+++ b/apps/sparkjava/04-environment-and-logging/build.gradle
@@ -16,7 +16,7 @@ run.doFirst {
 dependencies {
   // 3rd party
   implementation 'com.google.guava:guava:27.0.1-jre'
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'org.slf4j:slf4j-api:1.7.29'
   implementation 'org.slf4j:slf4j-simple:1.7.29'
   implementation 'com.sparkjava:spark-debug-tools:0.5'
diff --git a/apps/sparkjava/05-spring-data-standalone/build.gradle b/apps/sparkjava/05-spring-data-standalone/build.gradle
index bd25f7dd..f42bd1a5 100644
--- a/apps/sparkjava/05-spring-data-standalone/build.gradle
+++ b/apps/sparkjava/05-spring-data-standalone/build.gradle
@@ -21,7 +21,7 @@ dependencies {
 
   // 3rd party
   implementation 'com.google.guava:guava:27.0.1-jre'
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'com.squareup.moshi:moshi:1.9.2'
   implementation 'io.jsonwebtoken:jjwt:0.9.1'
   implementation 'org.hsqldb:hsqldb:2.5.0'
diff --git a/support/spark/jackson/build.gradle b/support/spark/jackson/build.gradle
index dc5da7f6..d08b3448 100644
--- a/support/spark/jackson/build.gradle
+++ b/support/spark/jackson/build.gradle
@@ -10,7 +10,7 @@ dependencies {
   implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.10.1'
   implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.10.1'
   implementation 'com.fasterxml.jackson.module:jackson-module-parameter-names:2.10.1'
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
 
   testImplementation 'junit:junit:4.+'
   testImplementation 'org.assertj:assertj-core:3.14.0'
diff --git a/support/spark/jwt/build.gradle b/support/spark/jwt/build.gradle
index 76c8617c..28ca2031 100644
--- a/support/spark/jwt/build.gradle
+++ b/support/spark/jwt/build.gradle
@@ -4,7 +4,7 @@ plugins {
 }
 
 dependencies {
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'io.jsonwebtoken:jjwt:0.9.1'
 
   testImplementation group: 'junit', name: 'junit', version: '4.+'
diff --git a/support/spark/moshi/build.gradle b/support/spark/moshi/build.gradle
index 2584e104..3144d27b 100644
--- a/support/spark/moshi/build.gradle
+++ b/support/spark/moshi/build.gradle
@@ -4,7 +4,7 @@ plugins {
 }
 
 dependencies {
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'com.squareup.moshi:moshi:1.9.2'
 
   testImplementation group: 'junit', name: 'junit', version: '4.+'
diff --git a/support/spark/spring-data/build.gradle b/support/spark/spring-data/build.gradle
index 47975973..68192a2d 100644
--- a/support/spark/spring-data/build.gradle
+++ b/support/spark/spring-data/build.gradle
@@ -1,7 +1,7 @@
 apply plugin: 'java-library'
 
 dependencies {
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'org.hibernate.javax.persistence:hibernate-jpa-2.1-api:1.0.2.Final'
   implementation 'org.hibernate:hibernate-core:5.4.10.Final'
   implementation 'org.hibernate:hibernate-entitymanager:5.4.10.Final'
diff --git a/support/spark/testing/build.gradle b/support/spark/testing/build.gradle
index 4606aa23..0813efd7 100644
--- a/support/spark/testing/build.gradle
+++ b/support/spark/testing/build.gradle
@@ -4,7 +4,7 @@ plugins {
 }
 
 dependencies {
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'com.squareup.okhttp3:okhttp:3.+'
   implementation 'junit:junit:4.+'
   implementation 'org.assertj:assertj-core:3.14.0'
diff --git a/support/spark/xsrf/build.gradle b/support/spark/xsrf/build.gradle
index 8f4ad994..10eba621 100644
--- a/support/spark/xsrf/build.gradle
+++ b/support/spark/xsrf/build.gradle
@@ -4,7 +4,7 @@ plugins {
 }
 
 dependencies {
-  implementation 'com.sparkjava:spark-core:2.9.1'
+  implementation 'com.sparkjava:spark-core:2.9.4'
   implementation 'io.jsonwebtoken:jjwt:0.9.1'
 
   testImplementation 'junit:junit:4.+'