For a long time we've been experimenting with IPv6 enabled services on the core of our network. Those users who were on IPv6-capable subnets could, if they enabled IPv6, talk to these services by changing the domain name of these from "ru.ac.za" to "ip6.ru.ac.za" (as in a.mail.ip6.ru.ac.za).
As of today we've dropped the ip6 prefix for IPv6 addresses. This means that all IPv6-enabled services publish both A and AAAA records, and machines that are IPv6-capable will probably prefer to use IPv6 by default. This effectively puts IPv6 into "production" on Rhodes' network.
This change will only affect people on subnets that support IPv6 router solicitation, viz the Africa Media Matrix (48), Struben building (88), RUCUS (115), CoE (116), Hamilton building (120), core services (128), staff wireless (232) and the test network (248).