The recommendation of using the most recent standard is very slightly inconsistent with this, because in rare cases your code could be reused in weird embedded

The recommendation of using the most recent standard is very slightly inconsistent with this, because in rare cases your code could be reused in weird embedded targets that only have an unmaintained proprietary C compiler. That was already rare in 2014 I think. Still, the situation might arise, just like you can still can find AS/400 machines or Cobol in production.