Change effective on 28 March 2019
Starting from March 27th, 2019, DNS targets for apps using the SSL Endpoint will use
<random-string>.ssl.herokudns.com, instead of
herokussl.com (for US apps) or
herokuapp.com (for EU apps). This change applies to apps in the Common Runtime, in both the EU and US region. SSL Endpoints made prior to this date will not be affected.