As from Q1 2017, the RadCloudUpload is internally referencing version 3 of the Amazon SDK for .NET. Hence, you will be able to use all new features that come with this version. The version 3 of the AWS SDK for .NET uses separate packages (dlls) for each service. The RadCloudUpload only references AWSSDK.Core.dll and AWSSDK.S3.dll.
For more information on how to use old version of the Amazon SDK with the RadCloudUpload, refer to this documentation article