diff --git a/HISTORY.md b/HISTORY.md
index 2fe856c..031bb62 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,3 +1,7 @@
+## v5.0.4
+* Ensures all requests have a `User-Agent` string, including `Data` requests.
+* Added missing `CancellationToken` to `GetCurrenciesAsync()` 
+
 ## v5.0.3
 * PR #47: Extra DI interfaces for DI support. Notification event and transaction status constants. Changed `Transaction.Description` return from object to string. Thanks granthoff1107! 
 
diff --git a/Source/Coinbase.Tests/ExtensionsForTesting.cs b/Source/Coinbase.Tests/ExtensionsForTesting.cs
index 5518034..a6238f6 100644
--- a/Source/Coinbase.Tests/ExtensionsForTesting.cs
+++ b/Source/Coinbase.Tests/ExtensionsForTesting.cs
@@ -3,6 +3,7 @@
 using FluentAssertions;
 using Flurl.Http.Testing;
 using Newtonsoft.Json;
+using Z.ExtensionMethods;
 
 namespace Coinbase.Tests
 {
@@ -29,5 +30,10 @@ public static HttpCallAssertion ShouldHaveRequestBody(this HttpTest test, string
          test.CallLog.First().RequestBody.Should().Be(json);
          return new HttpCallAssertion(test.CallLog);
       }
+
+      public static bool IsAppVeyor(this OperatingSystem os)
+      {
+         return Environment.GetEnvironmentVariable("APPVEYOR").IsNotNullOrWhiteSpace();
+      }
    }
-}
\ No newline at end of file
+}
diff --git a/Source/Coinbase.Tests/Integration/DataTests.cs b/Source/Coinbase.Tests/Integration/DataTests.cs
index dd88484..9d18c60 100644
--- a/Source/Coinbase.Tests/Integration/DataTests.cs
+++ b/Source/Coinbase.Tests/Integration/DataTests.cs
@@ -4,8 +4,10 @@
 using System.Net.Http;
 using System.Threading.Tasks;
 using FluentAssertions;
+using Flurl.Http;
 using Flurl.Http.Configuration;
 using NUnit.Framework;
+using Z.ExtensionMethods;
 
 namespace Coinbase.Tests.Integration
 {
@@ -13,6 +15,20 @@ public class DataTests
    {
       private CoinbaseClient client;
 
+      [OneTimeSetUp]
+      public void BeforeAllTests()
+      {
+         if( !Environment.OSVersion.IsAppVeyor() )
+         {
+            var webProxy = new WebProxy("http://localhost.:8888", BypassOnLocal: false);
+
+            FlurlHttp.Configure(settings =>
+               {
+                  settings.HttpClientFactory = new ProxyFactory(webProxy);
+               });
+         }
+      }
+
       [SetUp]
       public void BeforeEachTest()
       {
diff --git a/Source/Coinbase/CoinbaseClient.Data.cs b/Source/Coinbase/CoinbaseClient.Data.cs
index d86e65d..de3a7fc 100644
--- a/Source/Coinbase/CoinbaseClient.Data.cs
+++ b/Source/Coinbase/CoinbaseClient.Data.cs
@@ -40,7 +40,7 @@ public interface IDataEndpoint
       /// <summary>
       /// List known currencies. Currency codes will conform to the ISO 4217 standard where possible. Currencies which have or had no representation in ISO 4217 may use a custom code (e.g. BTC).
       /// </summary>
-      Task<PagedResponse<Currency>> GetCurrenciesAsync();
+      Task<PagedResponse<Currency>> GetCurrenciesAsync(CancellationToken cancellationToken = default);
 
       /// <summary>
       /// Get the API server time.
@@ -60,6 +60,7 @@ public partial class CoinbaseClient : IDataEndpoint
       Task<Response<Money>> IDataEndpoint.GetBuyPriceAsync(string currencyPair, CancellationToken cancellationToken)
       {
          return this.PricesEndpoint
+            .WithClient(this)
             .AppendPathSegments(currencyPair, "buy")
             .GetJsonAsync<Response<Money>>(cancellationToken);
       }
@@ -72,6 +73,7 @@ Task<Response<Money>> IDataEndpoint.GetBuyPriceAsync(string currencyPair, Cancel
       Task<Response<Money>> IDataEndpoint.GetSellPriceAsync(string currencyPair, CancellationToken cancellationToken)
       {
          return this.PricesEndpoint
+            .WithClient(this)
             .AppendPathSegments(currencyPair, "sell")
             .GetJsonAsync<Response<Money>>(cancellationToken);
       }
@@ -85,6 +87,7 @@ Task<Response<Money>> IDataEndpoint.GetSellPriceAsync(string currencyPair, Cance
       Task<Response<Money>> IDataEndpoint.GetSpotPriceAsync(string currencyPair, DateTime? date, CancellationToken cancellationToken)
       {
          var req = this.PricesEndpoint
+            .WithClient(this)
             .AppendPathSegments(currencyPair, "spot");
 
          if (!(date is null))
@@ -101,7 +104,8 @@ Task<Response<Money>> IDataEndpoint.GetSpotPriceAsync(string currencyPair, DateT
       /// <param name="currency">Base currency (default: USD)</param>
       Task<Response<ExchangeRates>> IDataEndpoint.GetExchangeRatesAsync(string currency, CancellationToken cancellationToken)
       {
-         var req = this.ExchangeRatesEndpoint;
+         var req = this.ExchangeRatesEndpoint
+            .WithClient(this);
 
          if (!(currency is null))
          {
@@ -114,9 +118,11 @@ Task<Response<ExchangeRates>> IDataEndpoint.GetExchangeRatesAsync(string currenc
       /// <summary>
       /// List known currencies. Currency codes will conform to the ISO 4217 standard where possible. Currencies which have or had no representation in ISO 4217 may use a custom code (e.g. BTC).
       /// </summary>
-      Task<PagedResponse<Currency>> IDataEndpoint.GetCurrenciesAsync()
+      Task<PagedResponse<Currency>> IDataEndpoint.GetCurrenciesAsync(CancellationToken cancellationToken)
       {
-         return this.CurrenciesEndpoint.GetJsonAsync<PagedResponse<Currency>>();
+         return this.CurrenciesEndpoint
+            .WithClient(this)
+            .GetJsonAsync<PagedResponse<Currency>>(cancellationToken);
       }
 
 
@@ -125,7 +131,16 @@ Task<PagedResponse<Currency>> IDataEndpoint.GetCurrenciesAsync()
       /// </summary>
       Task<Response<Time>> IDataEndpoint.GetCurrentTimeAsync(CancellationToken cancellationToken)
       {
-         return this.TimeEndpoint.GetJsonAsync<Response<Time>>(cancellationToken);
+         // Manually make this request outside the scope of .WithClient(this)
+         // because when UseTimeApi =true and when the user makes the first request,
+         // we need to know the server time but if we use .WithClient(this),
+         // we'll get stuck in a recursive situation with no base case
+         // to resolve the actual server time. So, we have to make this
+         // request out of scope of this configured client.
+         return this.TimeEndpoint
+            .WithHeader(HeaderNames.Version, ApiVersionDate)
+            .WithHeader("User-Agent", UserAgent)
+            .GetJsonAsync<Response<Time>>(cancellationToken);
       }
 
    }