Version 5.9.2 is available upstream. Please consider updating! It seems that version 5.9.2 is available upstream, while the latest version in the Gentoo tree is 9999. You think this warning is false? Read more about it here.
Zsh is a shell designed for interactive use, although it is also a
powerful scripting language. Many of the useful features of bash, ksh,
and tcsh were incorporated into zsh; many original features were
added.