Using the phone keypad to respond to a voice menu does not work properly on my Samsung Galaxy Tab A running Android 8.1.0. The version of Zoiper running is 2.8.15. I have Zoiper also on a Lenovo Tab 2 that works just fine. Both installs have the DTMF style set the same. The sites typically respond to the tone with a do not understand that response message. I believe it did respond correctly in the past since the Galaxy has been my default tablet for many months though not yet a year. (I.e have just started noticing this behavior in the last couple of weeks.)