At the moment, it's easy to know what features will be in 4.0 final by trying out one of hte release candidates (look for the VOTE threads on the dev@lucene list)
As far as distributed pivot faceting support: this has not been committed -- there is an open jira with a patch, however skimming the recent ocmments there seems to be some question as to wether it's out of date with the current code. The best way to ensure this makes it into 4.1 would be to try out hte patch, and report back in Jira your success/failures applying/using it. https://issues.apache.org/jira/browse/SOLR-2894 : Please pardon this if is and FAQ, but after searching the archives I : cannot get a clear answer. : : Does the new facet.pivot work with SOLRCloud? When I run SOLR 4 BETA : with zookeeper, even if I specify shards=1, pivoting does not seem to : work. The quickest way to demo this is with the velocity browse page : on the example data. The pivot facet for "cat,inStock" only appears : if I run without zookeeper. : : If this is known, can you please let me know if this is a defect in : beta that is expected to be working in GA or whether it will remain a : limition for some time. : : regards, : : Nick Koton : -Hoss