upgrade to a newer Markdown interpreter

[julienschmidt]

Your site is using Maruku, the default Markdown interpreter. Maruku is now obsolete and may cause builds to fail for sites with invalid Markdown or HTML. See https://help.github.com/articles/migrating-your-pages-site-from-maruku for more information on upgrading to a newer Markdown interpreter.

For information on troubleshooting Jekyll see:

https://help.github.com/articles/using-jekyll-with-pages#troubleshooting

[xaprb]

According to the docs, we also need to rename config.yml to _config.yml