A few customers find that there is a slight keyboard lag in iPhone 4S especially after the updates to newer versions of iOS. If users find the email or messaging becomes annoying because of the lag, then they must try these solutions:

Solution: Switch off documents and data in iCloud

• Go to the Settings menu of the iPhone 4S
• Tap on iCloud
• Look for Documents and Data and switch it off

If the keyboard lag vanishes and you are able to use your phone smoothly again, then you can go back to the Documents and Data and toggle it on once again.