Actually when I was using my sister's phone with iOS 6.x, there was this problem too.

And my iPhone 4 on iOS 7.x also had this problem.

I also noticed another irritation when using Whatsapp. When typing, the assistive touch button would be "pushed" to the top of the screen where I'd normally have it in the middle right. Sometimes it stays there at the top, sometimes it floats up for awhile, then goes back to original position.

Quite irritating and it only happens with Whatsapp. For other apps, it's a good girl and does what I tell it to: which is to stay where she's supposed to stay.

Another thing, I think it was promoted that you can reply messages from anywhere from the top Notification bar. Not sure if this applies to iMessage only cause I can't do it for Whatsapp. Maybe not fixed yet.

I can only click on the bar to shortcut me to Whatsapp. I think it works for Facebook Messenger although I didn't get to test it much.

Viva Madrid leather case

Agree with u. I got a replacement for my iPhone 4 last time in Manchester. It bought the phone from Maxis ten months previously. They did check my iPhone in their system and mentioned to me that it was a genuine one purchased in Malaysia. I assume they still practise same policy right now.

Going 6+ or exiting iOS altogether...? 

What's not running smoothly right now...? 

   

U disabled background app refresh for those chat apps but enabled notification for them. That's why. I opted for that coz can save battery.

Weird that I have no such problem... 

666devil did highlight Background App Refresh should be enabled for these apps...

And have you tried restoring your iPhone...?

Notification is just notification, some contents are not part of notifications, for example Facebook, unless you want to be notified for every single piece of news that crops up your News Feed... Background app refresh is more for content update in the background, that is if you don't want to wait for it to refresh ONLY when your app is active, hence Background...

They are totally separate functions...

There's a master switch to disable all background app refresh. Setting - general - background app refresh. It will overwrite all app refresh u set for each individual app. Go check .
If u open up notification page, it's no longer consider background app, hence will refresh the data. Good example is stock market. It will refresh the stock price ONLY every time  when u pull notification down even though background refresh is turned off. You can see it refresh from old to new price.
This is much better than unroot android that keep leaking data even though U turn off in settings.

Leak won't be so high. Seems ur iCloud synching many data using mobile network. Pls go settings - iCloud make sure all backup and data sync over mobile network is turned off. Photo stream will also suck data. Damn this iOS becoming as complicated as android....

Nvm... Buy again... We'll always welcome you back...  

Wth u sold off iphone due to perceived data leak? Then pls dont go android. U turn off in settings it won't obey will still leak. U need to know how to force stop app and disable background data. Rince and repeat if u need to restart phone.

Or try windows phone , I tested no data leak