Hello Windows Insiders! Well, it was sort of released in November 2015. Most reviews of the 950 and 950XL wrote about the bugs and poor software. The release in March 2016 was hardly publicised. If you blinked you missed it.
The same week the Build conference didn't even feature Windows 10 Mobile and as we drifted along Microsoft made the rather obvious statement that they weren't really focused on Windows 10 Mobile this year.
If you wanted to upgrade a handset then not only might you have found your handset removed from the list you had to proactively download an app to do it. Most "normal" users wouldn't even be aware it was launched.
Writing on the Windows Blog Dona Sarkar writes:
I know a lot of Insiders are wondering about Mobile. Just like we did after the release of the Windows 10 November Update – we are starting off by releasing PC builds from our Development Branch first and then start releasing Mobile builds a few weeks after. Right now, the team is laser-focused on preparing to release the Windows 10 Anniversary Update to Mobile devices and we think we’re almost ready. You can help us out by making sure you are running Build 14393.67 (KB3176931) on your phone and sending in feedback on any issues you run into via the Feedback Hub.
Hence it's even a debate as to whether, for the majority of users, Windows 10 Mobile, was ever launched at all. Most Microsoft journalists moved on to using a Google Nexus 6p a long time ago seeing that Microsoft are not that interested in their own mobile platform these days.
I guess there are odd diehards like me who keep a Lumia in a draw, pull it out occasionally, update the OS, check if any useful apps have been released, realise it doesn't matter and put it back in the draw.
Microsoft has otherwise stated they are decided to make sure anniversary update for home windows 10 cellular is of excessive first-rate, and if the remarks are right enough we are able to hopefully see that soon.