public enum VersionAccessType : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

public async Task WorkingWithVersions()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        using (VersionManager versionManager = geodatabase.GetVersionManager())
        {
            IReadOnlyList<string> versionNames = versionManager.GetVersionNames();

            Version defaultVersion = versionManager.GetDefaultVersion();

            string testVersionName = versionNames.First(v => v.Contains("Test"));
            Version testVersion= versionManager.GetVersion(testVersionName);

            Version qaVersion = defaultVersion.GetChildren().First(version => version.GetName().Contains("QA"));

            Geodatabase qaVersionGeodatabase = qaVersion.Connect();

            FeatureClass currentFeatureClass = geodatabase.OpenDataset<FeatureClass>("featureClassName");
            FeatureClass qaFeatureClass = qaVersionGeodatabase.OpenDataset<FeatureClass>("featureClassName");
        }
    });
}