I just got an email from Apple saying they've updated their app guidelines (probably because it's time for WWDC and also a side of ongoing litigation)
There's always that bit about protecting customers, whether they're trying to get their 30% cut of all you revenue or telling me there's something they don't like about my game but just can't articulate it.
Among the updated rules is one of my favorites: prohibiting "irrelevant information"
I don't remember what the previous version of the rule said exactly, but it's still pretty much the same. Irrelevant information is any mention of the competition.
This means (in a vague, bureaucraticaly weaselly, yet haughty way) you can't mention Android versions of your app in your app description or anywhere in the app (and you're taking your chances with links).
You can even have your app rejected if it displays ads that feature both App Store and Google Play badges for the app. (This happened to me with Unity Ads twice, second time because Unity forgot all about it and had to be persuaded yes, this is really happening, and advertisers need to make iOS-only versions of all their ads).
Never mind that someone (like me) might have both iOS and Android devices. It's "irrelevant information" and the user must be protected from it!