imapsync is a tool for facilitating incremental recursive IMAP transfers from one mailbox to another. It is useful for mailbox migration or backup, and reduces the amount of data transferred by only copying messages that are not present on both servers. Read, unread, and deleted flags are preserved, and the process can be stopped and resumed. The original messages can optionally be deleted after a successful transfer.
xNBD is yet another NBD (Network Block Device) server program, which is fully compatible with the NBD client driver in the Linux kernel. In comparison with the original NBD server, it provides possibly better I/O performance by using mmap(), concurrent access from multiple clients, distributed Copy-on-Write disk, and live storage migration for virtual machines.
XMT (XStream Migration Tool) is a library to migrate XStream serialized XML when the associated Java class evolves. XStream is a popular library to serialize a Java object to XML and back again, and XMT enables a smooth migration of this XML with the help of dom4j when you change the class definition of the Java object.