Wasn't windows 10 suppose to enable the LED notification in Lumia 730 / 735 and 930????I checked the microsoft forums about it and all the moderators answered saying that the function will be available in a future windows 10 preview update.
They stated the ability is in the OS. But, it would require firmware update to do. If they plan to, which they haven't official said they would, It's unlikely there would be a firmware update for those specific phones before the official Win 10 Mobile upgrades go live.