A recent update to Google Messages was found containing a string that indicated the app would stop working on uncertified Android devices starting March 31. This was spotted courtesy of XDA Developers' teardown of the app's version 7.2.203.
The change could be due to the rollout of end-to-end encryption feature for Rich Communication Service (RCS) messages. Now, a new app teardown by the folks at 9to5Google suggests that Google Duo will also stop working on unsupported Android phones in the future.
This was found on the latest version of Duo (version 123), which contains the following notice:
Duo is going away soon.
Because you’re using an unsupported device, Duo will unregister your account on this device soon. Download your Clips and call history to avoid losing them.
The app’s code also indicates that this upcoming change is related to “GmsCompliance" or Google Mobile Services (GMS). It's basically a collection of Google applications and APIs that support functionality across devices. Currently, even phones that are not certified to run GMS like those from Huawei can still use Duo.
When the upcoming change takes effect, Android phones that are not certified to use Play Services may soon be unable to run Duo. It remains unclear, though, when the app will stop working on unsupported devices.