This app was mentioned in 3 comments, with an average of 2.33 upvotes
Actually the Android version of the app was just released: https://play.google.com/store/apps/details?id=com.dexcom.follow
So you can pick your new phone based on actually phone stuff, not CGM because it works the same on both platforms. I guess with android you could also use the Nightscout stuff too, so that's a plus. (Nightscout is more less just an alternative to the Dexcom app. Sort of.)
If you're already invested into the Android ecosystem, I wouldn't switch. ESP considering Android M is coming, and it looks awesome. (DISCLAIMER: I am an avid iPhone user, am probably biased and I currently use a 6 Plus.)
Just searched the store for Dexcom. https://play.google.com/store/apps/details?id=com.dexcom.follow