Also on Android, Google decides what models of phones are able to use the Play Store. So unless you get into a third party store, or expect your users to side-load, that old smartphone might not be so useful.
The old smartphone is only used for testing, you can literally use whatever you want (with increasing limitations), if you really want you can use even an HTC dream with Android 2
Android studio on a modern computer is painful
Also on Android, Google decides what models of phones are able to use the Play Store. So unless you get into a third party store, or expect your users to side-load, that old smartphone might not be so useful.
The old smartphone is only used for testing, you can literally use whatever you want (with increasing limitations), if you really want you can use even an HTC dream with Android 2