I have finally gotten around to updating SD-6 on isocpp.org:

https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations

What's up there now differs from N4200 in just a few minor ways (according
to my intention and knowledge):

1. An updated document date and history.
2. A corrected typo ("removed" for "femoved").
3. HTML changes to reflect changes from last year's revision without using
CSS features (more <ins> and <del> tags).

But of course my fingers may have slipped at some point.

I have also produced a new revision, attached. The redlining is now relative
to what's on isocpp.org. Also, I have added some information about the C++17
changes approved in Urbana. At this point, I have made very few guesses; let
discussion begin (yeah, I know -- probably after the New Year).

I notice that Richard is behind quite a few of the new features, for almost
none of which is any feature-test macro mentioned in the document. [shaking
head] Richard, Richard. :-)

Also, I have a vague recollection that something happened in Rapperswil
that might require a new macro, but I'm no longer certain what it was. It
must have been formally approved as a library issue resolution in Urbana;
could it have been issue 2408, et possibly al.?

I'm sorry, but I personally just don't have the bandwidth to analyze issue
resolutions, especially for the library, to see if they really introduce new
features. Alisdair brought some to my attention for C++11, and I can't
remember how this one came to my attention. I wish we had a more reliable
process for handling library interface fixes.

--
Clark Nelson            Chair, PL22.16 (ANSI C++ standard committee)
Intel Corporation       Chair, SG10 (C++ SG for feature-testing)
clark.nelson_at_[hidden]  Chair, CPLEX (C SG for parallel language extensions)