You should normally not have to do anything unless you specifically want to use a different engine than kramdown.
The kramdown engine supersedes both the
Redcarpet engines and if you’re updating an existing site updating should be as simple as changing the Markdown setting to kramdown in your site’s configuration (or removing it entirely).
If you encounter issues with any of the Markdown engines try issuing the following gem command
gem install markdown
Copyright © 2016 Sverrir Sigmundarson, licensed under CC-BY-4.0.