Check out this article if you would like to know which iOS devices support 802.11v which the 804mesh APs makes use of for band steering and other wifi management.
https://support.apple.com/en-ca/HT202628
I can’t find a list of specific Android Devices right now.
Here is an interesting article from March 2015 that will be relevant in troubleshooting WiFi. It also mentions a bit about some 802.11 amendments that the 804mesh will be using.
https://wifinigel.blogspot.ca/2015/03/what-are-sticky-clients.html