Howdy! (Hi @pb66 - very long time since being active here indeed!)
It’s right that you do indeed need to be using HTTPS. Apple require that for apps these days. However there is an exception for the emonpi and *.local domains. I can’t add any arbitrary domain into there, because Apple would reject the app. Could it be that now your emonpi is called something different?
Also - should be a massive update coming to the iOS app soon - so watch out for that!