Add another info message in the getting started.

RadzenBlazorDemos/Pages/GetStarted.razor

@@ -25,6 +25,11 @@
 All interactive features of the Radzen Blazor components require interactivity of the container <code>.razor</code> file to be enabled or the <code>@@rendermode</code>
 attribute of the component to be set to one of the following values: <code>InteractiveServer</code>, <code>InteractiveAuto</code> or <code>InteractiveWebAssembly</code>.
 More info is available in the <RadzenLink Text="rendering mode article" Path="https://learn.microsoft.com/en-us/aspnet/core/blazor/components/render-modes?view=aspnetcore-8.0" target="_blank" /> from the official Blazor documentation.
+            </RadzenAlert>
+            <RadzenAlert AlertStyle="AlertStyle.Info" Variant="Variant.Flat" Shade="Shade.Lighter" AllowClose="false" class="rz-mb-12">
+                If you have upgraded your application to .NET 8 or .NET 9 follow the getting started instructions for the version you initially used - e.g.
+                <RadzenLink Path="get-started/net7-server" Text=".NET 7" /> or <RadzenLink Path="get-started/net6-server" Text=".NET 6"/>.
+These instructions assume the new application layout which uses rendering modes and was introduced with .NET 8.
             </RadzenAlert>
             @Installation(CurrentVersion)
             @Import(CurrentVersion)