Year 2000 Issues
We are starting to get a lot of Y2K compliance questions. The answer is that rsync has no Y2K problems. rsync uses 32 bit "seconds since 1970" date formats and thus has no problems with the turn of the century.You must remember though that rsync is part of a larger system. It relies on a transport mechanism (rsh, ssh etc) and many operating systems services (such as inetd, syslog etc). If any of these other parts fail then rsync will of course be affected.
Also remember that rsync comes with absolutely no warranty. It is up to you to test whether rsync is suitable in your computing environment, both before and after the turn of the century.