diff --git a/browserup-proxy-core/build.gradle b/browserup-proxy-core/build.gradle
index 7602ab83e..c78f44db4 100644
--- a/browserup-proxy-core/build.gradle
+++ b/browserup-proxy-core/build.gradle
@@ -87,7 +87,7 @@ dependencies {
     testImplementation 'org.eclipse.jetty:jetty-servlet:7.6.16.v20140903'
     testImplementation 'org.eclipse.jetty:jetty-servlets:7.6.16.v20140903'
     testImplementation 'org.hamcrest:hamcrest-library:1.3'
-    testImplementation ('org.mock-server:mockserver-netty:3.10.4') {
+    testImplementation ('org.mock-server:mockserver-netty:5.5.1') {
         exclude(module: 'logback-classic')
         exclude(module: 'netty-codec-socks')
         exclude(module: 'netty-buffer')
diff --git a/browserup-proxy-rest/build.gradle b/browserup-proxy-rest/build.gradle
index bd991e78d..5f461d8e7 100644
--- a/browserup-proxy-rest/build.gradle
+++ b/browserup-proxy-rest/build.gradle
@@ -80,7 +80,7 @@ dependencies {
     testImplementation 'org.codehaus.groovy:groovy-all:2.4.16'
     testImplementation 'org.codehaus.groovy.modules.http-builder:http-builder:0.7.1'
     testImplementation 'org.hamcrest:hamcrest-library:1.3'
-    testImplementation 'org.mock-server:mockserver-netty:3.10.8'
+    testImplementation 'org.mock-server:mockserver-netty:5.5.1'
     testImplementation 'org.mockito:mockito-core:2.23.4'
     testImplementation 'org.seleniumhq.selenium:selenium-api:3.4.0'
     testImplementation 'org.awaitility:awaitility:3.1.6'