Added warning to version 9 update process

prs.server/Forms/Configuration.xaml.cs

@@ -1,6 +1,8 @@
 using System.ComponentModel;
 using System.Linq;
 using System.Reflection;
+using System.Windows.Controls;
+using System.Windows.Documents;
 using System.Windows.Media;
 using Comal.Classes;
 using Comal.Stores;
@@ -110,11 +112,23 @@ public partial class Configuration : ThemableWindow
             return false;
         }
 
+        var content = new TextBlock
+        {
+            VerticalAlignment = System.Windows.VerticalAlignment.Center,
+            TextWrapping = System.Windows.TextWrapping.Wrap
+        };
+        content.Inlines.Add($"PRS Version {targetMajorVersion} is available!");
+        content.Inlines.Add(new LineBreak());
+        content.Inlines.Add(new LineBreak());
+        content.Inlines.Add(new Bold(new Run("Note: ")));
+        content.Inlines.Add("This version contains some significant changes to the database structure; it is advised that you " +
+            "back up your data before proceeding.");
+
         var res = MessageWindow.New()
             .Title($"PRS Version {targetMajorVersion}")
-            .Message($"PRS Version {targetMajorVersion} is available!")
+            .Content(content)
             .AddOKButton("Proceed")
-            .AddCancelButton()
+            .AddCancelButton("Skip for now")
             .Display()
             .Result;
         if(res != MessageWindowResult.OK)