Hello,
We will make sure that ejabberd compile with the upcoming 2.0 version and Erlang R12B-0.
We will not however support this version and will wait for maintenance releases before supporting the R12B series.
We need to validate the behaviour of ejabberd for production system on this new release and this will probably mean official support not before R12B-1 or R12B-2.
CEAN will follow the same trend and we will probably only support the R12B starting from R12B-1.