From what I see, if your FTP supports resume feature, you can upload files bigger than 50MB. It will be interrupted after you have uploaded 50MB. But you can resume later. I use DriveHQ FileManager. For a free service account, it keeps asking me to upgrade to premium service after uploaded 50MB. While I can click Ok to ignore it, it's quite annoying. So I upgraded later. Overall, I think the software and service are worth to upgrade.