The documentation is up to date and reflects which features are currently supported. We’re working on versioned documentation to make it even more clear, but right now the docs reflect best the 1.6 release.
With supported, we mean that we have the tests in place to avoid regression, the correctness of execution, take this API up in performance tests etc…
One of the major items we tackled when developing 1.6 was unifying the code between FT.AGGREGATE and FT.SEARCH to be better maintainable. As a consequence, certain functionality that is not documented - and hence not supported - got exposed. They are some of those unsupported easter eggs and we recommend not using them since
we don’t know if they are working correctly
we can’t guarantee that we will maintain this “hidden” API in future release.
That said. We do still envision to unify the two API’s, albeit we can’t commit on a timeline yet.
If you have a specific question on how to solve your specific search query, we’re more than happy to help, but I suggest to move that to another thread.