diff --git a/Vonage.Test/AccountTest.cs b/Vonage.Test/AccountTest.cs
index 10c846ea5..575bc46c2 100644
--- a/Vonage.Test/AccountTest.cs
+++ b/Vonage.Test/AccountTest.cs
@@ -1,4 +1,5 @@
 using System.Net;
+using System.Threading.Tasks;
 using Moq;
 using Vonage.Accounts;
 using Vonage.Common;
@@ -13,7 +14,7 @@ public class AccountTest : TestBase
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void CreateApiSecretAsync(bool passCreds)
+    public async Task CreateApiSecretAsync(bool passCreds)
     {
         //ARRANGE            
         var expectedUri = $"https://api.nexmo.com/accounts/{this.ApiKey}/secrets";
@@ -52,7 +53,7 @@ public async void CreateApiSecretAsync(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void GetAccountBalanceAsync(bool passCreds)
+    public async Task GetAccountBalanceAsync(bool passCreds)
     {
         //ARRANGE
         var expectedUri = $"{this.RestUrl}/account/get-balance?api_key={this.ApiKey}&api_secret={this.ApiSecret}&";
@@ -76,7 +77,7 @@ public async void GetAccountBalanceAsync(bool passCreds)
     }
 
     [Fact]
-    public async void GetAccountBalanceAsync_ShouldReturnBalance_GivenCredentialsContainSecuritySecret()
+    public async Task GetAccountBalanceAsync_ShouldReturnBalance_GivenCredentialsContainSecuritySecret()
     {
         var mockTimeProvider = new Mock<ITimeProvider>();
         mockTimeProvider.Setup(provider => provider.Epoch).Returns(10);
@@ -95,7 +96,7 @@ public async void GetAccountBalanceAsync_ShouldReturnBalance_GivenCredentialsCon
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void RetrieveApiSecretsAsync(bool passCreds)
+    public async Task RetrieveApiSecretsAsync(bool passCreds)
     {
         //ARRANGE            
         var expectedResponse = @"{
@@ -144,7 +145,7 @@ public async void RetrieveApiSecretsAsync(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void RetrieveSecretAsync(bool passCreds)
+    public async Task RetrieveSecretAsync(bool passCreds)
     {
         //ARRANGE            
         var secretId = "ad6dc56f-07b5-46e1-a527-85530e625800";
@@ -182,7 +183,7 @@ public async void RetrieveSecretAsync(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void RevokeSecretAsync(bool passCreds)
+    public async Task RevokeSecretAsync(bool passCreds)
     {
         //ARRANGE            
         var secretId = "ad6dc56f-07b5-46e1-a527-85530e625800";
@@ -210,7 +211,7 @@ public async void RevokeSecretAsync(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void SetSettingsAsync(bool passCreds)
+    public async Task SetSettingsAsync(bool passCreds)
     {
         //ARRANGE
         var expectedUri = $"{this.RestUrl}/account/settings";
@@ -254,7 +255,7 @@ public async void SetSettingsAsync(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void TopUpAsync(bool passCreds)
+    public async Task TopUpAsync(bool passCreds)
     {
         //ARRANGE            
         var expectedUri =
diff --git a/Vonage.Test/ConversionTest.cs b/Vonage.Test/ConversionTest.cs
index 65d811b86..ff52db1e3 100644
--- a/Vonage.Test/ConversionTest.cs
+++ b/Vonage.Test/ConversionTest.cs
@@ -1,4 +1,5 @@
-using Vonage.Conversions;
+using System.Threading.Tasks;
+using Vonage.Conversions;
 using Vonage.Request;
 using Xunit;
 
@@ -37,7 +38,7 @@ public void SmsConversion(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void SmsConversionAsync(bool passCreds)
+    public async Task SmsConversionAsync(bool passCreds)
     {
         var expectedUri = $"{this.ApiUrl}/conversions/sms";
         var expectedContent =
@@ -91,7 +92,7 @@ public void VoiceConversion(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void VoiceConversionAsync(bool passCreds)
+    public async Task VoiceConversionAsync(bool passCreds)
     {
         var expectedUri = $"{this.ApiUrl}/conversions/voice";
         var expectedContent =
diff --git a/Vonage.Test/NumberInsightsTests.cs b/Vonage.Test/NumberInsightsTests.cs
index 335b74d54..970805e54 100644
--- a/Vonage.Test/NumberInsightsTests.cs
+++ b/Vonage.Test/NumberInsightsTests.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Net;
+using System.Threading.Tasks;
 using Vonage.NumberInsights;
 using Vonage.Request;
 using Xunit;
@@ -114,7 +115,7 @@ public void TestAdvancedAsync(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void TestAdvancedAsyncAsync(bool passCreds, bool kitchenSink)
+    public async Task TestAdvancedAsyncAsync(bool passCreds, bool kitchenSink)
     {
         var expectedResponse = this.GetResponseJson();
         var expectedUri = $"{this.ApiUrl}/ni/advanced/async/json";
@@ -249,7 +250,7 @@ public void TestAdvancedNIRequestSync(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void TestAdvancedNIRequestSyncAsync(bool passCreds, bool kitchenSink)
+    public async Task TestAdvancedNIRequestSyncAsync(bool passCreds, bool kitchenSink)
     {
         //ARRANGE
         var expectedResponse = this.GetResponseJson();
@@ -498,7 +499,7 @@ public void TestBasicNIRequest(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void TestBasicNIRequestAsync(bool passCreds, bool kitchenSink)
+    public async Task TestBasicNIRequestAsync(bool passCreds, bool kitchenSink)
     {
         //ARRANGE
         var expectedUri = $"{this.ApiUrl}/ni/basic/json";
@@ -685,7 +686,7 @@ public void TestStandardNIRequest(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void TestStandardNIRequestAsync(bool passCreds, bool kitchenSink)
+    public async Task TestStandardNIRequestAsync(bool passCreds, bool kitchenSink)
     {
         //ARRANGE
         var expectedResponse = this.GetResponseJson();
diff --git a/Vonage.Test/PricingTests.cs b/Vonage.Test/PricingTests.cs
index f502fb559..4fbdd9f86 100644
--- a/Vonage.Test/PricingTests.cs
+++ b/Vonage.Test/PricingTests.cs
@@ -1,4 +1,5 @@
-using Vonage.Pricing;
+using System.Threading.Tasks;
+using Vonage.Pricing;
 using Vonage.Request;
 using Xunit;
 
@@ -72,7 +73,7 @@ public void GetPricingAllCountries(bool passCreds)
     [Theory]
     [InlineData(true)]
     [InlineData(false)]
-    public async void GetPricingAllCountriesAsync(bool passCreds)
+    public async Task GetPricingAllCountriesAsync(bool passCreds)
     {
         //ARRANGE
         var expectedUri =
@@ -194,7 +195,7 @@ public void GetPricingForCountry(bool passCreds)
     [Theory]
     [InlineData(true)]
     [InlineData(false)]
-    public async void GetPricingForCountryAsync(bool passCreds)
+    public async Task GetPricingForCountryAsync(bool passCreds)
     {
         //ARRANGE
         var expectedUri =
@@ -318,7 +319,7 @@ public void GetPricingForPrefix(bool passCreds)
     [Theory]
     [InlineData(true)]
     [InlineData(false)]
-    public async void GetPricingForPrefixAsync(bool passCreds)
+    public async Task GetPricingForPrefixAsync(bool passCreds)
     {
         //ARRANGE
         var expectedUri =
diff --git a/Vonage.Test/VerifyTest.cs b/Vonage.Test/VerifyTest.cs
index b7a864282..b1e538def 100644
--- a/Vonage.Test/VerifyTest.cs
+++ b/Vonage.Test/VerifyTest.cs
@@ -1,4 +1,5 @@
 using System.Net;
+using System.Threading.Tasks;
 using Vonage.Request;
 using Vonage.Verify;
 using Xunit;
@@ -150,7 +151,7 @@ public void RequestVerification(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void RequestVerificationAsync(bool passCreds, bool kitchenSink)
+    public async Task RequestVerificationAsync(bool passCreds, bool kitchenSink)
     {
         var expectedResponse = @"{
               ""request_id"": ""abcdef0123456789abcdef0123456789"",
@@ -246,7 +247,7 @@ public void TestCheckVerification(bool passCreds, bool kitchenSink)
     [Theory]
     [InlineData(true, true)]
     [InlineData(false, false)]
-    public async void TestCheckVerificationAsync(bool passCreds, bool kitchenSink)
+    public async Task TestCheckVerificationAsync(bool passCreds, bool kitchenSink)
     {
         var expectedResponse = @"{
               ""request_id"": ""abcdef0123456789abcdef0123456789"",
@@ -325,7 +326,7 @@ public void TestControlVerify(bool passCreds)
     [Theory]
     [InlineData(true)]
     [InlineData(false)]
-    public async void TestControlVerifyAsync(bool passCreds)
+    public async Task TestControlVerifyAsync(bool passCreds)
     {
         var expectedResponse = @"{
               ""status"": ""0"",
@@ -451,7 +452,7 @@ public void TestVerifySearch(bool passCreds)
     [Theory]
     [InlineData(false)]
     [InlineData(true)]
-    public async void TestVerifySearchAsync(bool passCreds)
+    public async Task TestVerifySearchAsync(bool passCreds)
     {
         var expectedResponse = @"{
               ""request_id"": ""abcdef0123456789abcdef0123456789"",