I’m living in a world that has to support a product which has many parts in C++ on Solaris, HP-UX, and OS/400 (in addition to Linux, AIX, and Windows). We can’t drop support yet for the AIX release that only support up to C++ 11 although they have a newer clang based compiler. HP-UX and Solaris native compilers only go to C++14. Those platforms have at least 5 years of enterprise support yet, but no new chipsets mean no extended compiler development. And up-to-date gcc doesn’t build there.

And then IBM’s OS/400 ILEC++ support isn’t even up to C++11.

It is hard to live in Enterprise software land where you support everything for a lot of years, but end up stuck on older third party libraries when they move to new standards to keep parity across your product line’s feature set.