After few additional adjustments made, I had re-submitted the app few days ago. Now it's live and optimized for iPhone 6 and iPhone 6 Plus!
Here are the steps I made:
- Added App icon (including Settings Icon and Spotlight Icon) & Launch images to
Images.xcassets
in proper resolution and naming of the files (self-explanatory as they are) was done as following:


Additionally added Launch Screen
file. Because Apple says it's important to add.

Made sure that App icon, Launch Image and Launch file sources were properly selected at Project Targets -> General

Adjusted all inner screens to fit with the iPhone 6 and iPhone 6 plus screens, of course!
Made sure that arm64
was included in Project Targets -> Build Settings
. (Bye bye iOS 5 support!)

Removed armv7
from Required device capabilities
(a.k.a. UIRequiredDeviceCapabilities) in info.plist

On iTunes Connect, added screenshots for 4.7 and 5.5 inches devices excluding the device status bar. [Screenshot Properties]