Just updated from version 5.3 to version 8 of C# esign SDK (integrating w/ .NET Framework 4.8 MVC App) to take advantage of “IncludeAnchorTabLocations”.
Didn’t realize it would mean completely rewriting everything to use async since the synchronous methods now just call the async method .GetResult()

public OAuth.OAuthToken RequestJWTUserToken(string clientId, string userId, string oauthBasePath, byteh] privateKeyBytes, int expiresInHours, List<string> scopes = null)
        {
            CancellationTokenSource cts = new CancellationTokenSource();
            return TryCatchWrapper(() => RequestJWTUserTokenAsync(clientId, userId, oauthBasePath, privateKeyBytes, expiresInHours, scopes, cts.Token).ConfigureAwait(false).GetAwaiter().GetResult());
        }

Took me way too long to figure out why the application was hanging. Warning to anyone out there upgrading to v8 -- beware of deadlocks if you’re not using the async methods!