I saw the following reference to v0.70 in the new v3.0.0beta3 document,
(and noted that I couldn't download this version from: http://perlrsync.sourceforge.net/):
For BackupPC to use Rsync you will also need to
install the perl File::RsyncP module, which is available from
http://perlrsync.sourceforge.net. Version 0.70
or later is required.