The 3.2.x release of the PHP client includes admin features - the ability to add and drop a secondary index on a bin of a given set, and getting info about the cluster ( info(), infoMany(), getNodes() ).
However, 3.3.0 is approaching, with useful new functionality - batch operations ( getMany(), existsMany() ) and multi-ops. Batch allows you to get back the record or metadata of multiple keys at once, while multi-ops allow you to do multiple bin operations on a record at once, then read it back.