It has been a long time coming but, Windows 10 Mobile users are now able to receive notifications across their Windows 10 Mobile device and Fitbit. Those on the Windows Insider Program in the Fast ring are receiving the update first, which adds a new option in the settings for "Notifications open beta" - presumably, it will roll out to those outside of the Fast ring and Insider program in the near future.
Discovered by qixiaoqiu on Reddit, the feature was expected to launch with Windows 10 Mobile Insider build 15216, however, following a dramatic scene of events with a number of incorrect builds releasing this week, Microsoft has postponed releasing new builds for the time being.
As a universal app, this feature will also be on the way for Windows 10 devices. Be prepared though, as a beta this feature is expected to be sporadic in whether it works or not, with one person already mentioning that roughly 90% of the in-app test notifications failed to work correctly.