A 4-esben van/lesz Posix ACL...
http://backuppc.sourceforge.net/BackupPC-4.0.0alpha3_doc.html#Step-5:-C…
Due to the use of rsync-3.X, acls and xattrs are supported, and many other useful options (but not all) are supported. Rsync protocol 30 supports the efficient incremental file list, which significantly improves memory usage and startup time. It also supports MD5 full-file checksums, which match BackupPC's new digest. That allows a full-file digest to be checked as easily as an mtime on the server side.
3-as széria: http://backuppc.sourceforge.net/faq/limitations.html