Today I discovered that when I attempt to remote control my phone, instead of seeing the phone screen I can only file share and see data about the phone. I tried to downgrade Host apk to an older version (15.5.39) without any luck.
It is a Samsung s5 running android 4.4.2.
No TeamViewer files/installs on PC or Android say they are new as of today (or recent).
Update: I tried the latest compatible version of android quicksupport. It added the ability to request a screenshot, but no remote control.
Update 2: I reinstalled teamviewer on the phone. No luck. I also tried to remote control my mother's phone (I help her out with tech stuff sometimes) and that allowed remote control as usual. Very odd.
Even though there are "better" android programs for screen mirroring and control, I try to be a Teamviewer purest. I guess I have to give that up : /