Relative NB here, have a 5 on latest OS (7.1). Initial condition was I'd get a (purchased) ringtone for an incoming call, but the set ringtone for an incoming text msg would NOT 'ring' (std stattaco setting). But neither the up nor the down volume buttons were working either. I could set any ringtone for incoming calls and it'd 'ring' during changing the setting. For incoming texts, setting ANY sound would not cause the corresponding sound to run (i.e., while changing, it'd normally sound). I powered off n back on. Volume buttons then worked fine. And the text sounds came back on. Sounds like a SW bug somewhere. Tried setting several options (e.g. Do Not Disturb off then back on to it's normal (for me) setting, etc. All to no avail. Hence the power off n on.