Here, You are going to get a detailed guide to fix typing lag issue on your iPhone 4 Running iOS 7.0.
Although, iOS 7 in iPhone 4 is a better choice for your operations but this is somewhat overloaded for iPhone 4, and this is due to lower RAM. iPhone 4 contain only 512 MB RAM and many iPhone 4 users complained about the high latency when typing in iOS 7 like even you just call the Keyboard, it await 5-15 seconds.
Surely it bring a bad experience and make your mind once to downgrade back iOS 6 urgently, but problem is here that you are late. Because Apple has stopped signing iOS 6.1.3 for iPhone 4, so you can only stay in the iOS 7 and continue to endure those unacceptable lags.
However , There is an easy way to fix this keyboard “lag” issue, but it’s simply more of a temporary fix rather than a permanent one, since we are hoping that Apple will hear about the bug and issue a small update to fix it sometimes in the near future. The keyboard lag problem lies within iCloud, which is an odd place to have a keyboard lag issue, but many iPhone 4S users have sworn by this fix.
It is actually very simple to fix this typing lag issue on iPhone 4, you simply log in iCloud in iOS 7 settings app, close the Document and Data” option, then the issue can be satisfactorily resolved. Although you may feel this way weird, but it is really useful.
Here is the Guide;
How to fix iPhone 4 Lag Issue?
Go to Settings app >> iCloud
Log in iCloud with your Apple ID
Find out Documents & Data option, which is located above the Find My iPhone, then tap it.
After tapping Document and Data option, there will open up another window where you will see a toggle switch. Turn it off if it already isn’t by toggling switch on the left side.
After disabling Documents & Data, the keyboard should work just fine, but be sure to open up iMessage or another typing app and try it out just to make sure.
Afterward, you can turn back on Document & Data sync if you need to, but if you open iCloud >> Storage & Backup, the keyboard problem is said to appear again, so you will have to run off Documents & Data sync again if you do that.
Surprisingly, this solution is almost “perfectly fixed” all keyboard delay issues of the iPhone 4 users have encountered. However, if this doesn’t fix it for you, you can try a last resort fix. You can open up the settings app and navigate to General >> Reset >> Reset All Settings. This will only reset the settings and it won’t delete any data or media that you have stored on your device, but you will have to go back into the Settings app and change everything back to how you had them before. However, this also worked to fix the keyboard lag issue.