So I found a fix that worked for me. I tried to post it here a few weeks ago but this stupid f****g iOS update has messed up my phone to the point that it freezes every time I back space and I lose everything I wrote so I gave up. Anyways I'm following this post and I get an email every time someone posts on this forum and after seeing so many people having to do a compleat reset on their phone, I decided to try and write this one more time. I've posted a fix on this forum in the past which ended up not working, after about two hours the pop up came back. I gave up on trying to fix it and just tried to ignore it after that happened but after I found myself looking at windows phones I decided to try fixing it one more time. Anyeays here's what I did. It's a vary simple fix.
The first step is the most important.
1. Use the USB cable to connect your phone to your computer and sync it to your iTunes. Simple right?
2. After you do that, go to your iTunes account page on your computer, scroll down, and look for the option to "reset all download warnings".
That's all you have to do. Two steps and it's fixed. The reason it's important to sync your phone is because, for me, there was no option to "rest all download warnings" with out the phone being synced. After I did that I restarted my phone and got one more pop up but this time it told me what my phone was trying to download. It was a digital booklet for a Kings of Leon album I bought on my phone through iTunes. I also went to that web page that apple made, people have posted the link above, and did that thing that took the U2 album off my iTunes store purchased page. I didn't buy or even want it anyways. I did that before I did the reset all download warnings thing. I don't know It that made a difference but it's worth doing it just in case. So I didn't have to download any digital booklets onto my computer and I didn't have to restore my phone. Try this before you do anything like a full restore.
It's been three or four weeks sense I did this fix and no pop ups. I hope it works for you. Good luck.