Like many, I find that having a good clean way of deleting all text messages to be really important and needed. For IOS 6, there were one or two Jailbreak apps that could do it well. For IOS 7, I have read about the tweak DeleteAllMessages which is supposed to work... but I've tried that on IOS 8 (on my 5S) and it doesn't work. I can't find any other reasonable solution for this important problem... I know about the new IOS 8 feature of deleting messages after 30 days, or 1 year, etc... but I find that 1) 30 days is too long, 2) the message are not completely delete but leave the threads (conversations?) hanging behind... There are apparently expensive PC solutions to clean/erase the iphone, but they aren't very appealing as a routine solution. Finally after having all my messages pile up without a solution, I just went in with iFunBox and deleted smb.db* (in /var/mobile/Library/SMS). I rebooted right afterwards. It seems to work... Have I done something really terrible, corrupting my iphone? If not, why is it so difficult to write an app that just deletes these few files? Anyways... I guess its a solution to this long standing problem... i'm going to try to write a little shell script to do this within IOS so i don't need iFunBox.