You're right. But with S3io most of the action happens on the client side and it does work with sig. v4 which provides better integrity checking for large files

You're right. But with S3io most of the action happens on the client side and it does work with sig. v4 which provides better integrity checking for large files, the problem with Frankfurt is not very big, it's just that I can't automatically detect the region by the bucket name on the back end. But it should be fixable.