The system shell is immutable, as already explained in my previous post. In no system you expect the system shell to be allowed to change semantics. Any complaints that it's "not updateable" are nonsense. You can update the system shell when you update the complete system - incl all app packages. And only then. What use has an "update of system shell" anyway? Isn't it like so far all packages worked great with the "old" shell? So why do you need updates? (NB I'm not talking about security bugfixes, which have to get done unconditionally, but in a way that's 100% backward compatible, i.e. doesn't change semantics of the shell commands)

/j