On our project we run Solr 4.2 but we're migrating to latest SolrCloud.
We use optimistic locking, and when we post new documents we directly ask the version with the "versions" parameter. The response is in a "adds" field.
I can't even find a doc explaining that but it works
With Solr 5 (we did a few tests some time ago), 6.2 and 6.4.1 the Solr response has these "adds" but they're lost by the SolrJ client when aggregating responses from different Shards.
I have a patch that I'll propose via Github.