In April 2018, a new version of the app formerly known as Slow Feeds will be released with a new name. Slow Feeds 5 will become Web Subscriber 5.
Web Subscriber 5 will feature everything you could get in Slow Feeds and much more. Web Subscriber will no longer be just a special needs feed reader but will also be useful for people who just want to subscribe to stuff on the web without knowing much about RSS etc.
So if you are an existing Slow Feeds user, be prepared to look for the app under its new iPhone/iPad display name Web Sub and the new submarine icon!