This is a journaling archiver optimized for user-level incremental backup of
directory trees. It supports AES-256 encryption, 5 multi-threaded compression
levels, and content-aware file fragment level deduplication. For backups it
adds only files whose date has changed, and keeps both old and new versions.
You can roll back the archive date to restore from old versions of the
archive. The default compression level is faster than zip usually with better
compression. zpaq uses a self-describing compressed format to allow for future
improvements without breaking compatibility with older versions of the
program.
