The controversy began in mid-September when Mullenweg wrote a blog post criticizing WP Engine for disabling the ability for users to see and track the revision history for every post. Mullenweg believes this feature is essential for protecting user data and accused WP Engine of turning it off by default to save money. In response, WP Engine sent a cease-and-desist letter to Mullenweg and Automattic, asking them to withdraw their comments.