I have IOS 8 and I want to know how to save ALL of my notifications. What I mean is, I unlock the phone and then the notification disappears and I didn't read it. I have looked all over and there's no way I've found.
Settings > Notifications > Messages > Show in Notification Centre > … you can set up to 10 recent items
then all you need to do is swipe your screen from the top down & there they are [though if you've never used that before you'll probably need to clear a whole lot of other stuff first time & trim which apps actually need to be in there.]
You can't have all - only the last 10.