S4 UK Sim free phones are now receiving the big update from Samsung. This is BTU devices.

Improvements and fixes in the new Software Update:
-New Camera firmware
-Smearing issue has been fixed (Purple effect while scrolling)
-Smart Pause Toggle
-Move Apps to SD Card
-HDR Video (Can record HDR video)
-Semi-transparent status bar
-New Icons in Settings
-Secure boot status (About Phone)
-Increase legibility (Display) (New feature)

The update is 347mb. If you haven’t received it go to settings, about device, software update.

The version number after update is i9505XXUBMGA.