I try to use "Easy Customization" for most of my customization of Emacs. Some of my customizations are changes to the defaults, i. e.
sentence-end-base gets customized from:
When a new Emacs version is released, I have to go through all my customizations to see if the default has changed so that I need to reflect that in my customization as well.
Some/most customizable variables have information about when their default value was introduced or changed, for example:
(defcustom sentence-end-base "[.?!]\"'”)}]*" "Regexp matching the basic end of a sentence, not including following space." :group 'paragraphs :type 'string :version "22.1")
How would a sniplet look like that prompts for the Emacs version used previously and then lists all variables and faces that were customized and whose default has changed since that Emacs version?