This option specifies that the item was first introduced in
@var{package} version @var{version}, or that its default value was
changed in that version. This keyword takes priority over :version.
+The value of @var{package} is a symbol and @var{version} is a string.
The @var{package} and @var{version} must appear in the alist
@code{customize-package-emacs-version-alist}. Since @var{package} must
be unique and the user might see it in an error message, a good choice