I guess it depends on what you mean by new API - in 1.1.1 at least this is no longer deprecated - i think i remember reading that the entire mapred package was prematurely deprecated, and this was un-deprecated in a later release.
If by new API, you mean the mapreduce package over mapred, then the OutputFormats themselves have an associated OutputCommitter, which is acquired via the OutputFormat.getOutputCommitter
method