Here the author claims you must purchase the commercial license: <a href="https:&#x2F;&#x2F;github.com&#x2F;usablica&#x2F;intro.js&#x2F;issues&#x2F;464#issuecomment-194775516" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;usablica&#x2F;intro.js&#x2F;issues&#x2F;464#issuecomment...</a>