docs(common): Document NuGet v2 EOL (#2136)

Co-authored-by: Dimo Dimov <[email protected]>

Author: github-actions[bot]

installation/nuget.md

@@ -159,6 +159,18 @@ The `Telerik.UI.for.Blazor` NuGet package and most of its dependencies reside on
 
 > Make sure that the `key` values in the `packageSourceMapping` section match the `key` values in the `packageSources` section, otherwise you will get a "Package not found" error.
 
+
+## Obsolete Telerik NuGet URL
+
+In addition to feed URL `https://nuget.telerik.com/v3/index.json`, there is also an obsolete NuGet v2 server at `https://nuget.telerik.com/nuget`, which is no longer recommended.
+
+> The NuGet v2 server at `https://nuget.telerik.com/nuget` will be sunset in November 2024.
+>
+> The new v3 protocol offers faster package searches and restores, improved security, and more reliable infrastructure.
+>
+> To redirect your feed to the NuGet v3 protocol, all you have to do is to change your NuGet package source URL to `https://nuget.telerik.com/v3/index.json`.
+
+
 ## Troubleshooting
 
 See the [NuGet Troubleshooting]({%slug troubleshooting-nuget%}) article for tips about common pitfalls when working with the Telerik NuGet feed.

troubleshooting/nuget-feed.md

@@ -21,6 +21,7 @@ Regardless of the cause for the issue, it is recommended that you start from the
 * [Error `503 Service Unavailable`](#error-503-service-unavailable)
 * [Message about package `version not found`](#package-version-not-found)
 * [Error `Unable to resolve ... . PackageSourceMapping is enabled`](#unable-to-resolve-package-due-to-packagesourcemapping)
+* [Error `Failed to retrieve information about ... from remote source`](#failed-to-retrieve-information-from-remote-source)
 
 ## Tips for Handling Common NuGet Issues
 
@@ -107,6 +108,16 @@ Incorrect package source mapping can result in errors similar to:
 
 The solution is to check the **Package Source Mapping** settings in Visual Studio, or [review all applicable `NuGet.Config` files](https://learn.microsoft.com/en-us/nuget/consume-packages/configuring-nuget-behavior#config-file-locations-and-uses) on the machine. Then, [adjust the package source mapping configuration]({%slug installation/nuget%}#package-source-mapping).
 
+## Failed to Retrieve Information from Remote Source
+
+An attempt to use the [obsolete Telerik NuGet v2 feed]({%slug installation/nuget%}#obsolete-telerik-nuget-url) after November 2024 will result in an error:
+
+`Failed to retrieve information about 'Telerik.UI.for.Blazor' from remote source 'https://nuget.telerik.com/nuget/FindPackagesById()?id='Telerik.UI.for.Blazor'&semVerLevel=2.0.0'.`
+
+The solution is to [use the Telerik NuGet v3 feed]({%slug installation/nuget%}).
+
+Another possible reason for the same error is an incorrect NuGet feed URL.
+
 ## See Also
 
 * [Setting Up the Online Private Telerik NuGet Feed]({%slug installation/nuget%})