I Have just purchased Microsoft office for my iPad but cannot download it because I don't have the latest version of iOS but I cannot upload version 8 cos I don't have enough space. I have tried deleting stuff but it is just not working.
iPad, iOS 7.1
I would be careful about how you go about updating, in order to avoid many of the problems others have had. For one thing, I would not do an install on top of your old system, but rather do a "clean system install" in order to get rid of your corrupted and garbage files in your old system. They can cause you problems and make your life on your iPad miserable.
The first thing you should do is have your backups completed. It's preferable to have your backups done on your iTunes program on your computer, as that's the most complete. Be sure you understand what won't be backed up, so you can save them another way. Read the Apple Support documents on it.
Then after that, use your iTunes program to reset your device to its factory default state, as a clean and fresh iPad, as if it came right out of the factory doors. Then you can restore your data from the backup you have on iTunes. The following are the Apple Support documents on what I just said.
Choosing an iOS Backup Method (Should I Use iTunes or iCloud to back up ...)
https://support.apple.com/kb/HT5262
Back up and Restore your iOS Device with iCloud or iTunes
http://support.apple.com/kb/ht1766
iTunes: About iOS Backups
http://support.apple.com/kb/ht4946
Create and Delete iPhone, iPad and iPod Touch Backups in iTunes
http://support.apple.com/kb/ht4946
iOS: Troubleshooting Encrypted Backups
http://support.apple.com/kb/TS5162
Use iTunes to Restore your iOS Device to Factory Settings
Unable to upload newest version iOS
