This hack will allow you to enable LED notification on Lumia 730, 830, 950 and 950XL. The hacker says 930 has LED too but he was unable to get it working right now. The 830 uses its windows button as notification LED. Follow these steps to enable LED on your supported Lumia.
-Go to iutool path(extracted i386.zip folder) in cmd with admin rights.
Connect Ur phone with USB..
-Type “iutool -l” to see if the device is connected and recognized.
1. put the cab to a new folder like c:\cabs
2. then type: iutool -V -p c:\cabs
3. it should push the cab to the device and start the update.
4. there might be a error 0x8024a110 but it should work.
5. the device will automatically reboot very soon and go to flash mode (gears) to apply the cab.
6. Typical data migration wizard will launch and LED notification should be working for your phone.
If it does not work, you will have interop unlock windows 10 mobile and follow two additional steps. Download this if you own a Lumia 730 and 830 and this if you have a Lumia 950 / xl. Extract it and import them using a registry editor. It should be working by now.