I just updated to Android 5.1.1 on my Galaxy S6. When I used to go to advanced calling (which I previously had activated), there used to be a checkbox that I could check or uncheck to turn advanced calling off. I no longer have that checkbox. I spoke to someone at technical support and they told me I no longer have the option to turn off HD voice (advanced calling) as the software update, "embedded HD voice in the system." Can anyone confirm this? I used to turn it off when I was in a weak VoLTE area and I started dropping calls. Do others notice that the checkbox has been removed?