We are planning to discontinue the support for both iOS 10 and Android OS 4 in the near future. If your device is able to support a newer iOS/Android version, we would encourage you to update to a newer version as soon as you can.
 
We'd love to keep supporting older devices, but some of the 3rd party libraries we depend on have decided to discontinue the support for these two OS.
 
We realize that this is a disappointment for the users affected, and we sincerely apologise for the inconvenience.

We will notify players once we have more details about the timeline for discontinuing support of iOS 10 and Android OS 4.