Ultimate FTP supports two transfer modes: Binary and ASCII. The FTP protocol's maximum supported file size is
2^63 bytes =
9,223,372 TB. However, some underlying filesystems do not support large file size.
FAT32 are two examples; they support
4GB maximum file size respectively. For other filesystems, see this table.
There is still a workaround for the filesystems that can't store files larger than
4GB. The stream-based file transfer API supports reading file from small pieces and combine them all together to have the large file.