I want to upgrade my iphone 4. What should I do? Which OS?

I have never updated my iphone. It is still having ios 4 in it. Now, most apps are not getting supported by ios 4. They require ios 5. But whenever i go to itunes to upgrade it shows to upgrade to ios 7. I have heard that ios 7 is not good for iphone 4. What should i do?

Who told you that iOS 7 is not good
you should definitely get it upgraded so that you can use various features such as iCloud and much more

It is no longer possible to upgrade to iOS 5 or 6 for the iPhone 4. You'll have to either stick with iOS 4 or upgrade to the iOS 7. I would advise against the upgrade, because it makes your iPhone 4 terribly slow.

If you want to upadate to iOS 5 or 6.
Just download iPhone 4 iOS 5 IPSW file from this site.
www.ipswdownloader.com/

Open itunes Under summary tab press shift button and click on update. Now select downloaded iOS 5 ipsw file and itune will update to iOS 5.

If you want to update it to iOS 7.it run awesome on iPhone 4.so just feel free to update to iOS 7.0.3.