It depends on which carrier you use. On T-Mobile, the ONLY Windows Phone running the 1709 branch that is compatible with TMO's bands and VoLTE is the Alcatel Idol 4S. That's it. I believe AT&T still supports the AT&T-branded Lumia 950. Someone on AT&T would have to confirm this. As far as functionality, outside of Microsoft's own apps, very little is working.
My understanding is that any T-Mobile phone made prior to mid-2016 will be cut off. It's all about e911 from what I remember - this is not new. I'm curious as to why you had to manually edit the APN settings on a T-Mobile-branded device.
So it's July 2nd and my Lumia 640 LTE has survived the 3g deactivation and continues to have full service. As for manually setting up the APNs, automatic provisioning activated voice and sms, but I couldn't send or receive mms picture messages until I manually added separate internet and mms apns.
Now, if there was a way to install a browser that was a little bit more up to date than IE and a PDF reader, that would be about all I need.
Surprised, but happy for you. My non-VoLTE 950 is now relegated to wi-fi duty. As for browsing, I've been running Edge for years on it. And for .pdfs, I have PDF Viewer Plus installed. Enjoy and Go 640!
So I continue to use the 640 LTE as my daily driver. I updated it to Windows 10 Mobile using unofficial methods which restored a significant amount of functionality to the browser and system in general. It cost me the Here Wego navigation app though.
The absence of WhatsApp and Signal are the two most noticeable missing links. But I d have telegram working.
I'm pretty satisfied with the situation at this point.