Now, of course - a lot of bug fixes. Its surely a good idea to upgrade. But that doesn't answer my question. So a quick look at C++ compiler support showed that there is some interesting features, and mostly first C++26 support becoming available is one of them. Other features are more important to me though.
GCC 14 adds support for std::generator to coroutines. I'm not a coroutine user though, which makes this a nice to have. But the code example shows you how to traverse a tree with std::generator without using much else from coroutines, maybe this is a little more interesting then I thought...
Explicit object member functions may get overlooked, but its also known as deducing this. Its a great way to implement CRTP and has other uses. This one is interesting. It also allows you to only have one implementation for member functions which so far needed to exist for const and non-const instances.
I'm not sure if I have a use for the new stacktrace library, but its nice to have this enabled by default now. Also std::inout_ptr/std::out_ptr seems nice, but not sure where I would use them. But good to know that there is more now in our language to express such things when calling C functions.