[samtoday]

I believe it is a Samsung Galaxy 2. A quick search yielded:

http://bgr.com/2017/01/26/donald-trumps-android-phone/

https://www.cnbc.com/2017/03/29/donald-trump-apple-iphone-an...

[quickthrower2]

That's a bit cheapskate for a president.

[lightbyte]

Bit too risky to upgrade, don't want the POTUS's phone to spontaneously combust.