Honestly I've had no issues with Whatsapp notifications since August, the only time it doesn't work is of course when battery is too low & battery saver mode is on. Apart from that it works so well I often had to mute a bunch of groups so I don't get disturbed 

http://www.wpcentral.com/developers-leak-n...ws-phone-81-sdk

- NEW PlayTo support
- NEW Single sign-in for apps (like on Windows 8) with Microsoft Account; sign in will persist across devices + apps with permissions prompt
- NEW YouTube Player (see lede image) including HTML5 video support (video playback doesn't have to be full screen)  And you get custom UI, so YouTube Closed Captions are in
- NEW File picker (see above image)
- NEW Geofencing API for location-based reminders
- NEW Background tasks: Bluetooth signal strength, Chat message notification, Device connection change, Device use trigger, Gatt characteristic notification, Location, Push notification, Rfcomm connection, System event, Timer
- NEW Slide down to close apps
- NEW Navigation bar color selection
- NEW USB choices
- NEW Updated camera layout, similar to Windows 8.1 (see photo below)
- VPN (Virtual Private Network)
- OneDrive (previously SkyDrive) with integrated file browser (just like Windows 8.1)
- Filter through installed apps by usage/install date
- Select multiple tiles when customising the Start screen [FALSE]
- More efficient multitasking
- Ability to install apps on inserted SD Cards
- Internet Explorer 11 improved with WebGL and Normal mapping support
- Separate volume controls for ringer, media, etc.
- Bing smart search (similar search system as Windows 8.1)
- Xbox Music and Xbox Video as standalone apps instead of the Music + Video Hub (allowing more updates to be pushed)
- Redesigned Xbox Game Hub
- Twitter integrated more deeply into the contacts Hub
- Facebook account option REMOVED (updated)
- Quick settings access (Wi-Fi, Bluetooth) by doing a quick swipe from the top of the screen
- Action Center accessed by doing a full swipe from up to the bottom (separate from the Notification Center)
- Silent notifications which go directly to the Action center
- Possibility to mark a Live Tile as read by swiping from the left of said tile
- 'Cortana' smart agent performs the same tasks as Siri and Google Now and even more, including data from Foursquare  (MS INVEST)
- Auto-updates for apps (just like Windows 8.1)
- Better backup functionality
- Improved keyboard
- Bluetooth 4.0 LE (to non-Lumia Windows Phones)
- Feature to mirror Windows Phone screens to TVs and/or monitors

Darn...

Started to love my 1520 even more. 

New firmware update for Lumia 1520? 
    Improvements to Bluetooth connection quality
    Improvements to headset detection
    Improvements to stability and performance

http://www.nokia.com/gb-en/support/product...softwareupdate/
http://www.wpcentral.com/lumia-1520-picks-...e-united-states

Seems it would be fix the screen sensitivity issue.