From what I've read on the forums, by the developers, is that the backup and restore process on Android has been a technical nightmare for them and it's fragile

From what I've read on the forums, by the developers, is that the backup and restore process on Android has been a technical nightmare for them and it's fragile as it is. I presume that since they have limited resources they can only put so much effort into adding the feature to iOS (and improving it on Android) and have been concentrating on improved groups, group calling, Desktop calling, user name support, etc.