Adding deprecation messages to the README.md (#1661)

* Adding deprecation messages to the README.md

* moving things around

README.md

@@ -3,6 +3,21 @@
 | [Conceptual documentation](https://github.com/AzureAD/azure-activedirectory-library-for-dotnet/wiki#documentation) | [Code Samples](https://github.com/azure-samples?utf8=✓&q=active-directory-dotnet) | [Reference Docs](https://docs.microsoft.com/active-directory/adal/microsoft.identitymodel.clients.activedirectory) | [Developer Guide](https://aka.ms/aaddev) | [API Reference](https://docs.microsoft.com/en-us/dotnet/api/microsoft.identitymodel.clients.activedirectory?view=azure-dotnet) |
 | ------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ | ---------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
 
+## Update to MSAL.NET now!
+
+[MSAL.NET](https://github.com/AzureAD/microsoft-authentication-library-for-dotnet) is the new authentication library to be used with the Microsoft identity platform
+
+Building on top of ADAL, MSAL works with the new and Open ID Connect certified Azure AD V2 endpoint and the new social identity solution from Microsoft, Azure AD B2C.
+
+ADAL.NET is in maintenance mode and no new features will be added to ADAL.NET anymore. All our ongoing efforts will be focused on improving the new [MSAL.NET](https://github.com/AzureAD/microsoft-authentication-library-for-dotnet). MSAL’s documentation also contains a [migration guide]( https://docs.microsoft.com/en-us/azure/active-directory/develop/msal-net-migration) which simplifies upgrading from ADAL.NET, including how to migrate Xamarin.iOS apps using brokers.
+
+## ADAL.NET 2.x is no longer supported
+
+ADAL.NET 2.x is no longer supported. ADAL.NET 3.x became generally available more than 3 years ago, superseding ADAL 2.x which was last released in August 2017
+If you are still using 2.x, we recommend that you update directly to MSAL.NET
+
+## ADAL.NET
+
 Active Directory Authentication Library for .NET (ADAL.NET) is an easy to use authentication library. You can use ADAL.NET to acquire **security tokens to access protected Web APIs**, for instance Microsoft Graph, or another Web APIs. ADAL.NET is available on various .NET Desktop/Mobile platforms to acquire a token for the signed-in user ( Windows desktop, UWP, Windows 8.1, Xamarin iOS and Xamarin Android). It can also be used in Web applications and Web APIs (ASP.NET, .NET Core, ASP.NET Core) that call other Web APIs in the name of a user, or without a user. ADAL.NET takes advantage of Windows Server Active Directory and Windows Azure Active Directory.
 
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