diff --git a/QuickChart/QuickChart.cs b/QuickChart/QuickChart.cs
index 61cc620..a914717 100644
--- a/QuickChart/QuickChart.cs
+++ b/QuickChart/QuickChart.cs
@@ -3,177 +3,177 @@ using System.Net.Http;
 using System.Text;
 using System.Text.Json;
 using System.IO;
+using System.Text.Json.Serialization;
 
-namespace QuickChart
+namespace QuickChart;
+
+internal class QuickChartShortUrlResponse
 {
-    internal class QuickChartShortUrlResponse
-    {
 #pragma warning disable IDE1006 // Naming Styles
-        public bool status { get; set; }
-        public string url { get; set; }
+    public bool status { get; set; }
+    public string url { get; set; }
 #pragma warning restore IDE1006 // Naming Styles
-    }
+}
 
-    public class Chart
+public class Chart
+{
+    public int Width { get; set; }
+    public int Height { get; set; }
+    public double DevicePixelRatio { get; set; }
+    public string Format { get; set; }
+    public string BackgroundColor { get; set; }
+    public string Key { get; set; }
+    public string Version { get; set; }
+    public string Config { get; set; }
+
+    public string Scheme { get; set; }
+    public string Host { get; set; }
+    public int Port { get; set; }
+
+    private static readonly HttpClient Client = new();
+
+    public Chart(string scheme = null, string host = null, int? port = null)
     {
-        public int Width { get; set; }
-        public int Height { get; set; }
-        public double DevicePixelRatio { get; set; }
-        public string Format { get; set; }
-        public string BackgroundColor { get; set; }
-        public string Key { get; set; }
-        public string Version { get; set; }
-        public string Config { get; set; }
+        this.Width = 500;
+        this.Height = 300;
+        this.DevicePixelRatio = 1.0;
+        this.Format = "png";
+        this.BackgroundColor = "transparent";
 
-        public string Scheme { get; set; }
-        public string Host { get; set; }
-        public int Port { get; set; }
-
-        private static readonly HttpClient Client = new HttpClient();
-
-        public Chart(string scheme = null, string host = null, int? port = null)
+        if (host != null)
         {
-            this.Width = 500;
-            this.Height = 300;
-            this.DevicePixelRatio = 1.0;
-            this.Format = "png";
-            this.BackgroundColor = "transparent";
-
-            if (host != null)
+            this.Host = host;
+            if (scheme != null)
             {
-                this.Host = host;
-                if (scheme != null)
-                {
-                    this.Scheme = scheme;
-                    this.Port = port ?? (scheme == "http" ? 80 : 443);
-                }
-                else
-                {
-                    this.Scheme = "https";
-                    this.Port = 443;
-                }
+                this.Scheme = scheme;
+                this.Port = port ?? (scheme == "http" ? 80 : 443);
             }
             else
             {
                 this.Scheme = "https";
-                this.Host = "quickchart.io";
                 this.Port = 443;
             }
         }
-
-        public string GetUrl()
+        else
         {
-            if (this.Config == null)
-            {
-                throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
-            }
-
-            var builder = new StringBuilder();
-            _ = builder.Append("w=").Append(this.Width.ToString());
-            _ = builder.Append("&h=").Append(this.Height.ToString());
-
-            _ = builder.Append("&devicePixelRatio=").Append(this.DevicePixelRatio.ToString());
-            _ = builder.Append("&f=").Append(this.Format);
-            _ = builder.Append("&bkg=").Append(Uri.EscapeDataString(this.BackgroundColor));
-            _ = builder.Append("&c=").Append(Uri.EscapeDataString(this.Config));
-            if (!string.IsNullOrEmpty(this.Key))
-            {
-                _ = builder.Append("&key=").Append(Uri.EscapeDataString(this.Key));
-            }
-            if (!string.IsNullOrEmpty(this.Version))
-            {
-                _ = builder.Append("&v=").Append(Uri.EscapeDataString(this.Version));
-            }
-
-            return $"{this.Scheme}://{this.Host}:{this.Port}/chart?{builder}";
+            this.Scheme = "https";
+            this.Host = "quickchart.io";
+            this.Port = 443;
         }
-
-        public string GetShortUrl()
-        {
-            if (this.Config == null)
-            {
-                throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
-            }
-
-            var options = new JsonSerializerOptions
-            {
-                IgnoreNullValues = true
-            };
-
-            var json = JsonSerializer.Serialize(new
-            {
-                width = this.Width,
-                height = this.Height,
-                backgroundColor = this.BackgroundColor,
-                devicePixelRatio = this.DevicePixelRatio,
-                format = this.Format,
-                chart = this.Config,
-                key = this.Key,
-                version = this.Version,
-            }, options);
-
-            var url = $"{this.Scheme}://{this.Host}:{this.Port}/chart/create";
-
-            var response = Client.PostAsync(
-                url,
-                new StringContent(json, Encoding.UTF8, "application/json")
-            ).Result;
-
-            if (!response.IsSuccessStatusCode)
-            {
-                throw new ApiException("Unsuccessful response from API", response);
-            }
-
-            var responseText = response.Content.ReadAsStringAsync().Result;
-            var result = JsonSerializer.Deserialize<QuickChartShortUrlResponse>(responseText);
-            return result.url;
-        }
-
-        public byte[] ToByteArray()
-        {
-            if (this.Config == null)
-            {
-                throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
-            }
-
-            var options = new JsonSerializerOptions
-            {
-                IgnoreNullValues = true
-            };
-
-            var json = JsonSerializer.Serialize(new
-            {
-                width = this.Width,
-                height = this.Height,
-                backgroundColor = this.BackgroundColor,
-                devicePixelRatio = this.DevicePixelRatio,
-                format = this.Format,
-                chart = this.Config,
-                key = this.Key,
-                version = this.Version,
-            }, options);
-
-            var url = $"{this.Scheme}://{this.Host}:{this.Port}/chart";
-
-            var response = Client.PostAsync(
-                url,
-                new StringContent(json, Encoding.UTF8, "application/json")
-            ).Result;
-
-            return !response.IsSuccessStatusCode
-                ? throw new ApiException("Unsuccessful response from API", response)
-                : response.Content.ReadAsByteArrayAsync().Result;
-        }
-
-        public void ToFile(string filePath) 
-            => File.WriteAllBytes(filePath, this.ToByteArray());
     }
 
-    public class ApiException : Exception
+    public string GetUrl()
     {
-        public ApiException(string message, HttpResponseMessage response) : base(message) 
-            => this.Response = response;
+        if (this.Config == null)
+        {
+            throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
+        }
 
-        public HttpResponseMessage Response { get; private set; }
+        var builder = new StringBuilder();
+        _ = builder.Append("w=").Append(this.Width);
+        _ = builder.Append("&h=").Append(this.Height);
+
+        _ = builder.Append("&devicePixelRatio=").Append(this.DevicePixelRatio);
+        _ = builder.Append("&f=").Append(this.Format);
+        _ = builder.Append("&bkg=").Append(Uri.EscapeDataString(this.BackgroundColor));
+        _ = builder.Append("&c=").Append(Uri.EscapeDataString(this.Config));
+        if (!string.IsNullOrEmpty(this.Key))
+        {
+            _ = builder.Append("&key=").Append(Uri.EscapeDataString(this.Key));
+        }
+        if (!string.IsNullOrEmpty(this.Version))
+        {
+            _ = builder.Append("&v=").Append(Uri.EscapeDataString(this.Version));
+        }
+
+        return $"{this.Scheme}://{this.Host}:{this.Port}/chart?{builder}";
     }
+
+    public string GetShortUrl()
+    {
+        if (this.Config == null)
+        {
+            throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
+        }
+
+        var options = new JsonSerializerOptions
+        {
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+        };
+
+        var json = JsonSerializer.Serialize(new
+        {
+            width = this.Width,
+            height = this.Height,
+            backgroundColor = this.BackgroundColor,
+            devicePixelRatio = this.DevicePixelRatio,
+            format = this.Format,
+            chart = this.Config,
+            key = this.Key,
+            version = this.Version,
+        }, options);
+
+        var url = $"{this.Scheme}://{this.Host}:{this.Port}/chart/create";
+
+        var response = Client.PostAsync(
+            url,
+            new StringContent(json, Encoding.UTF8, "application/json")
+        ).Result;
+
+        if (!response.IsSuccessStatusCode)
+        {
+            throw new ApiException("Unsuccessful response from API", response);
+        }
+
+        var responseText = response.Content.ReadAsStringAsync().Result;
+        var result = JsonSerializer.Deserialize<QuickChartShortUrlResponse>(responseText);
+        return result.url;
+    }
+
+    public byte[] ToByteArray()
+    {
+        if (this.Config == null)
+        {
+            throw new NullReferenceException("You must set Config on the QuickChart object before generating a URL");
+        }
+
+        var options = new JsonSerializerOptions
+        {
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+        };
+
+        var json = JsonSerializer.Serialize(new
+        {
+            width = this.Width,
+            height = this.Height,
+            backgroundColor = this.BackgroundColor,
+            devicePixelRatio = this.DevicePixelRatio,
+            format = this.Format,
+            chart = this.Config,
+            key = this.Key,
+            version = this.Version,
+        }, options);
+
+        var url = $"{this.Scheme}://{this.Host}:{this.Port}/chart";
+
+        var response = Client.PostAsync(
+            url,
+            new StringContent(json, Encoding.UTF8, "application/json")
+        ).Result;
+
+        return !response.IsSuccessStatusCode
+            ? throw new ApiException("Unsuccessful response from API", response)
+            : response.Content.ReadAsByteArrayAsync().Result;
+    }
+
+    public void ToFile(string filePath) 
+        => File.WriteAllBytes(filePath, this.ToByteArray());
+}
+
+public class ApiException : Exception
+{
+    public ApiException(string message, HttpResponseMessage response) : base(message) 
+        => this.Response = response;
+
+    public HttpResponseMessage Response { get; private set; }
 }
diff --git a/QuickChart/QuickChart.csproj b/QuickChart/QuickChart.csproj
index 6d88026..9e9232f 100644
--- a/QuickChart/QuickChart.csproj
+++ b/QuickChart/QuickChart.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <TargetFrameworks>netcoreapp3.1;netstandard2.0;net472</TargetFrameworks>
+    <TargetFrameworks>net7.0</TargetFrameworks>
     <PackOnBuild>true</PackOnBuild>
     <Authors>Ian Webster</Authors>
     <Copyright>Ian Webster</Copyright>