diff --git a/build.gradle b/build.gradle
index 272205785b..e9fac934ef 100644
--- a/build.gradle
+++ b/build.gradle
@@ -34,7 +34,7 @@ buildscript {
     ext.disruptor_version = constants.getProperty("disruptorVersion")
     ext.metrics_version = constants.getProperty("metricsVersion")
     ext.metrics_new_relic_version = constants.getProperty("metricsNewRelicVersion")
-    ext.okhttp_version = '3.5.0'
+    ext.okhttp_version = '3.14.1'
     ext.netty_version = '4.1.22.Final'
     ext.typesafe_config_version = constants.getProperty("typesafeConfigVersion")
     ext.fileupload_version = '1.3.3'
diff --git a/testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/DriverDSLImpl.kt b/testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/DriverDSLImpl.kt
index 14bbe399f8..b7dcaa6d12 100644
--- a/testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/DriverDSLImpl.kt
+++ b/testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/DriverDSLImpl.kt
@@ -307,7 +307,7 @@ class DriverDSLImpl(
 
         while (process.isAlive) try {
             val response = client.newCall(Request.Builder().url(url).build()).execute()
-            if (response.isSuccessful && (response.body().string() == "started")) {
+            if (response.isSuccessful && (response.body()?.string() == "started")) {
                 return WebserverHandle(handle.webAddress, process)
             }
         } catch (e: ConnectException) {
diff --git a/testing/test-utils/src/main/kotlin/net/corda/testing/http/HttpUtils.kt b/testing/test-utils/src/main/kotlin/net/corda/testing/http/HttpUtils.kt
index 5e87f4e36b..4f4675a0fe 100644
--- a/testing/test-utils/src/main/kotlin/net/corda/testing/http/HttpUtils.kt
+++ b/testing/test-utils/src/main/kotlin/net/corda/testing/http/HttpUtils.kt
@@ -47,7 +47,7 @@ object HttpUtils {
     private fun makeRequest(request: Request) {
         val response = client.newCall(request).execute()
         if (!response.isSuccessful) {
-            throw IOException("${request.method()} to ${request.url()} returned a ${response.code()}: ${response.body().string()}")
+            throw IOException("${request.method()} to ${request.url()} returned a ${response.code()}: ${response.body()?.string()}")
         }
     }
 }