Why do you think this is?

Some reason I can think of:

- Can't update the compiler (eg, porting the code base to the new compiler is too complicated)

- No compiler support for the new standard that target a specific platform that one still want to support.

- Too much work to update the whole code base to work with the new standard.

- A 3rd party library is not supporting new standard yet.

- The team is reluctant to have to learn new technologies.

Some are somewhat valid reason, some are less, some are indication of deeper problems.

(P.S: My C++ code base is using C++20. Didn't move to C++23 yet because I think some customers might not be ready for it yet for one of these reasons, but I'm going to push for it at some point.)