diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/EyesAndEars.UWP.csproj b/src/EyesAndEars.UWP/EyesAndEars.UWP/EyesAndEars.UWP.csproj
index c8238c3..65487fe 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/EyesAndEars.UWP.csproj
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/EyesAndEars.UWP.csproj
@@ -108,6 +108,8 @@
     <UseVSHostingProcess>false</UseVSHostingProcess>
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
+    <EnableGatekeeperAnalysis>true</EnableGatekeeperAnalysis>
+    <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
     <OutputPath>bin\x64\Release\</OutputPath>
diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml b/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml
index f28d788..c40d0dc 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml
@@ -164,7 +164,8 @@
                              ToolTipService.ToolTip="This is a link to a webpage with information about Nicola and the project."/>
 
             <TextBox x:Name="WebAddressBox" Grid.Column="1" FontSize="26"
-                     Padding="20" Text="http://3.9.19.84" TextAlignment="Left"
+                     Text="{x:Bind _vm.BaseURL , Mode=OneWay}"
+                     Padding="20" TextAlignment="Left"
                      HorizontalAlignment="Stretch" TextWrapping="NoWrap"
                      Margin="0" VerticalAlignment="Center"
                      HorizontalContentAlignment="Left"
diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml.cs b/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml.cs
index 8781945..df08721 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml.cs
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/MainPage.xaml.cs
@@ -1,6 +1,7 @@
 using EyesAndEars.UWP.Services;
 using EyesAndEars.UWP.ViewModels;
 using System;
+using System.Threading;
 using Windows.ApplicationModel;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
@@ -11,6 +12,7 @@ namespace EyesAndEars.UWP {
 
         MainPageVM _vm = new MainPageVM();
         DispatcherTimer _dispatcherTimer = new DispatcherTimer();
+        string _baseURL = "http://3.9.19.84";
 
         public MainPage() {
             InitializeComponent();
@@ -20,14 +22,14 @@ namespace EyesAndEars.UWP {
         }
 
         void SetVersionNumber() {
-            Package package = Package.Current;
-            PackageId packageId = package.Id;
-            PackageVersion version = packageId.Version;
+            var package = Package.Current;
+            var packageId = package.Id;
+            var version = packageId.Version;
             VersionNumber.Text = $"Ver: {version.Major}.{version.Minor}.{version.Build}.{version.Revision}";
         }
 
-        void IntialiseDataContext() {
-            var url = WebAddressBox.Text;
+        async void IntialiseDataContext() {
+            _vm.BaseURL = await DataServices.GetBaseURLAsync();
             _vm.Device1 = DataServices.CreateFallBackDevice(1);
             _vm.Device2 = DataServices.CreateFallBackDevice(2);
             _vm.Device3 = DataServices.CreateFallBackDevice(3);
@@ -45,21 +47,22 @@ namespace EyesAndEars.UWP {
         }
 
         async void UpdateViewModel(object sender, object e) {
-            var url = WebAddressBox.Text;
-            _vm.Device1 = await DataServices.UpdateDevice(url, 1);
-            _vm.Device2 = await DataServices.UpdateDevice(url, 2);
-            _vm.Device3 = await DataServices.UpdateDevice(url, 3);
-            _vm.Device4 = await DataServices.UpdateDevice(url, 4);
-            _vm.Device5 = await DataServices.UpdateDevice(url, 5);
-            _vm.Device6 = await DataServices.UpdateDevice(url, 6);
+            var url = _vm.BaseURL;
+            if (!string.IsNullOrEmpty(url)) {
+                _vm.Device1 = await DataServices.UpdateDevice(url, 1);
+                _vm.Device2 = await DataServices.UpdateDevice(url, 2);
+                _vm.Device3 = await DataServices.UpdateDevice(url, 3);
+                _vm.Device4 = await DataServices.UpdateDevice(url, 4);
+                _vm.Device5 = await DataServices.UpdateDevice(url, 5);
+                _vm.Device6 = await DataServices.UpdateDevice(url, 6);
+            }
         }
 
-        void RefreshButton_Click(object sender, RoutedEventArgs e) {
+        void RefreshButton_Click(object sender, RoutedEventArgs e) =>
             IntialiseDataContext();
-        }
 
-        void SaveURLButton_Click(object sender, RoutedEventArgs e) {
-            // WORK ON THIS WENT YOU HAVE A LIVE SYSTEM WORKING WITH KNOWABLE DEFAULTS.
+        async void SaveURLButton_Click(object sender, RoutedEventArgs e) {
+            await DataServices.SaveBaseURLAsync(WebAddressBox.Text);
         }
     }
 }
diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/Properties/Default.rd.xml b/src/EyesAndEars.UWP/EyesAndEars.UWP/Properties/Default.rd.xml
index af00722..d5fe98b 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/Properties/Default.rd.xml
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/Properties/Default.rd.xml
@@ -25,7 +25,26 @@
     
     
     <!-- Add your application specific runtime directives here. -->
-
-
+    
+    <!-- Note: The Inclusion of the JSON Serialization Converters.
+    ===========================================================================
+    The Json.Serialization converts are needed so the app. can operate as "release".
+    Without them, the app. throw a System.Reflection.MissingMetadataException
+    when you try and run the app. using the "release" compiler setting.
+    I added the lines of code below based on the Issue raised and discussed on
+    GitHub. The link is https://github.com/dotnet/runtime/issues/978.
+    -->
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterString" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterUri" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterBoolean" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterInt32" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterInt16" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterByte" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterDecimal" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterGuid" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterEnum" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterDateTime" Dynamic="Required All" />
+    <Type Name="System.Text.Json.Serialization.Converters.JsonConverterDateTimeOffset" Dynamic="Required All" />
+    
   </Application>
 </Directives>
\ No newline at end of file
diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/Services/DataServices.cs b/src/EyesAndEars.UWP/EyesAndEars.UWP/Services/DataServices.cs
index f966fe6..d795050 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/Services/DataServices.cs
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/Services/DataServices.cs
@@ -3,6 +3,7 @@ using System;
 using System.Diagnostics;
 using System.Text.Json;
 using System.Threading.Tasks;
+using Windows.Storage;
 using Windows.UI;
 using Windows.UI.Xaml.Media;
 
@@ -22,15 +23,21 @@ namespace EyesAndEars.UWP.Services {
                 return new Device(deviceId, r, s, c);
             }
             catch (Exception e) {
-                Debug.WriteLine($"ERROR: {e.Message}");
+                Debug.WriteLine(e.Message);
                 return CreateFallBackDevice(deviceId);
             }
         }
 
         static SolidColorBrush UpdateStatusColour(string status) {
-            return status.Equals("on", StringComparison.OrdinalIgnoreCase) ?
+            try {
+                return status.Equals("on", StringComparison.OrdinalIgnoreCase) ?
                 new SolidColorBrush(Colors.SeaGreen) :
                 new SolidColorBrush(Colors.DarkRed);
+            }
+            catch (Exception e) {
+                Debug.WriteLine(e.Message);
+                return new SolidColorBrush(Colors.DarkOrange);
+            }
         }
 
         /* Note: The Purpose of Mapping a Factory to a Gallery Device.
@@ -78,13 +85,25 @@ namespace EyesAndEars.UWP.Services {
         }
 
         static LightReading MapToLightReading(string json) {
-            var reading = JsonSerializer.Deserialize<LightReading>(json);
-            return reading;
+            try {
+                var reading = JsonSerializer.Deserialize<LightReading>(json);
+                return reading;
+            }
+            catch (Exception e) {
+                Debug.WriteLine(e.Message);
+                return CreateDefaultLightReading();
+            }
         }
 
         static DeviceStatus MapToDeviceStatus(string json) {
-            var status = JsonSerializer.Deserialize<DeviceStatus>(json);
-            return status;
+            try {
+                var status = JsonSerializer.Deserialize<DeviceStatus>(json);
+                return status;
+            }
+            catch (Exception e) {
+                Debug.WriteLine(e.Message);
+                return CreateDefaultDeviceStatus();
+            }
         }
 
         public static Device CreateFallBackDevice(int deviceId) {
@@ -95,5 +114,37 @@ namespace EyesAndEars.UWP.Services {
             var d = new Device(deviceId, r, s, c);
             return d;
         }
+
+        static LightReading CreateDefaultLightReading() =>
+            new LightReading { id = 0, reading = 999, time = DateTime.Now };
+
+        static DeviceStatus CreateDefaultDeviceStatus() =>
+            new DeviceStatus { id = 0, status = "err", time = DateTime.Now };
+
+        public static async Task SaveBaseURLAsync(string contents) {
+            try {
+                var storageFolder = ApplicationData.Current.LocalFolder;
+                var baseURLFile = await storageFolder.CreateFileAsync("baseURL.txt",
+                    CreationCollisionOption.ReplaceExisting);
+                await FileIO.WriteTextAsync(baseURLFile, contents);
+            }
+            catch (Exception e) {
+                Debug.WriteLine(e.Message);
+            }
+        }
+
+        public static async Task<string> GetBaseURLAsync() {
+            try {
+                var storageFolder = ApplicationData.Current.LocalFolder;
+                var baseURLFile = await storageFolder.GetFileAsync("baseURL.txt");
+                var text = await FileIO.ReadTextAsync(baseURLFile);
+                return text;
+            }
+            catch (Exception e) {
+                Debug.WriteLine(e.Message);
+                return "";
+            }
+            
+        }
     }
 }
diff --git a/src/EyesAndEars.UWP/EyesAndEars.UWP/ViewModels/MainPageVM.cs b/src/EyesAndEars.UWP/EyesAndEars.UWP/ViewModels/MainPageVM.cs
index 7d4c379..1f74c35 100644
--- a/src/EyesAndEars.UWP/EyesAndEars.UWP/ViewModels/MainPageVM.cs
+++ b/src/EyesAndEars.UWP/EyesAndEars.UWP/ViewModels/MainPageVM.cs
@@ -28,6 +28,17 @@ namespace EyesAndEars.UWP.ViewModels {
             Device3 = g3;
         }
 
+        string _baseURL;
+        public string BaseURL {
+            get { return _baseURL; }
+            set {
+                if (value != _baseURL) {
+                    _baseURL = value;
+                    NotifyPropertyChanged("BaseURL");
+                }
+            }
+        }
+
         Device _device1;
         public Device Device1 {
             get { return _device1; }