To Start: Which Versions this is about...

To comment on the Bluetooth LE API, it would be useful to specify versions, but that is hard:
Since Windows 10, Microsoft are promising to keep you out of the version hassle, and update to new versions automatically. Consequently, they don't make it exactly easy to find version numbers.

I am remote debugging on a laptop with Windows 10 installed. The Computer Properties say
'Windows 10 Pro'.
Settings -> System -> About says:

Edition: Windows 10 Pro
Version: 1511
OS Build: 10586.218

The development environment is Visual Studio 2015 Update 2 on Windows 7, using a Remote Debugger. Visual Studio  creates the project for an UWP app or dll with the default settings for the target system:

.Net Core target version: 10.0.10586, minimal: 10.0.10240

Part of the Bluetooth LE API is, for example, the Windows.Devices.Bluetooth.Advertisement namespace, and at the time of writing this, it is documented on MSDN here.
The individual class documentations for this namespace state:

"Device family: Universal, introduced version 10.0.10240.0"

However, it is not easy to find out the actual current version of .Net Core on the computer.
It is not installed under C:\Windows\Microsoft\.Net\Framework and Framework64. Apparently, .Net Core is part of the system, and the best guess is that it has the version of the system itself (10.0.10586).