-# Allow substitutions and expansions in the prompt, necessary for vcs_info.
-setopt promptsubst
-# Load vcs_info to display information about version control repositories.
-autoload -Uz vcs_info
-# Only look for git and mercurial repositories; the only I use.
-zstyle ':vcs_info:*' enable git hg
-# Set style of vcs_info display. The current branch (green) and vcs (blue) is
-# displayed. If there is an special action going on (merge, rebase) it's also
-# displayed (red).
-zstyle ':vcs_info:*' formats \
-"(%{${fg[green]}%}%b%{${fg[default]}%}:\
+# VCS_Info was added in 4.3.9.
+if [[ $ZSH_VERSION == (4.3.<9->|4.<4->*|<5->*) ]]; then
+ # Allow substitutions and expansions in the prompt, necessary for
+ # vcs_info.
+ setopt promptsubst
+ # Load vcs_info to display information about version control repositories.
+ autoload -Uz vcs_info
+ # Only look for git and mercurial repositories; the only I use.
+ zstyle ':vcs_info:*' enable git hg
+ # Set style of vcs_info display. The current branch (green) and vcs (blue)
+ # is displayed. If there is an special action going on (merge, rebase)
+ # it's also displayed (red).
+ zstyle ':vcs_info:*' formats \
+ "(%{${fg[green]}%}%b%{${fg[default]}%}:\