I use a CVS (or to be more precise Git) checkout of Zsh to get the current
completions.
# Make sure every entry in $fpath is unique.
typeset -U fpath
+# ~/.zsh/functions/completion is a symbolic link to the Completion directory
+# of a Zsh CVS checkout. Use it to get the newest completions if available.
+if [[ -d ~/.zsh/functions/completion ]]; then
+ fpath=(~/.zsh/functions/completion/*/*(/) $fpath)
+fi
# Set correct fpath to allow loading my functions (including completion
# functions).
fpath=(~/.zsh/functions $fpath)