Basic Authentication Retirement MS Graph

Question

Can someone tell me if it will still be possible to use following authentication method with MS Graph after October 13, 2020?

public static async Task<string> GetUserAccessTokenAsync()
{
    String APIToken = "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX";
    String LoginMail = "[email protected]";
    String LoginWachtwoord = "xxxxxxxxxxx";

    UserPasswordCredential userPasswordCredential = new UserPasswordCredential(LoginMail, LoginWachtwoord);

    AuthenticationContext authContext = new AuthenticationContext("https://login.microsoftonline.com/diekeure.be");

    //Console App for Microsoft Graph
    AuthenticationResult token = await authContext.AcquireTokenAsync("https://graph.microsoft.com/", APIToken, userPasswordCredential);

    return token.AccessToken;
} /* GetUserAccessTokenAsync */

public static GraphServiceClient GetAuthenticatedClient()
{
    GraphServiceClient graphClient = new GraphServiceClient(
        new DelegateAuthenticationProvider(
            async (requestMessage) => {
                string accessToken = await GetUserAccessTokenAsync();

                        // Append the access token to the request.
                        requestMessage.Headers.Authorization = new AuthenticationHeaderValue("bearer", accessToken);
            }));
    return graphClient;
} /* GetAuthenticatedClient */

-> await graphClient....

Nuget package: Microsoft.IdentityModel.Clients.ActiveDirectory v3.19.8

I'm not really sure of this won't work either

Answer 1

Your sample isn't using Basic Authentication, it is using the OAuth Password grant. While not a very secure authentication mechanism (since you have to store a password), it is quite different than Basic Auth.

The email you referenced is also specific to legacy services like Exchange Web Services (EWS). Microsoft Graph is not a legacy API, it is the recommended/modern REST API for Microsoft services.