Updating from iOS 7.1.3 to 8.3

[Sinmbo Ogunjinmi]

Hello everyone.
I have been trying to update my iPhone 5s running an iOS 7.1.2 to iOS 8.3. Anytime I tried downloading through the phone it generates an error. It also generates an error when I try it through iTunes. Please what can I do?

 

[kch50428]

Update to 8.4 which is the current iOS.

 

[Bigeric23]

What error are you receiving? Are you getting the same error both ways?