The MiVoice Office 250 / Mitel 5000 is in its final months of sale, I believe.
I believe you can still order digital cards for IP Office, but I believe the digital phones themselves are discontinued. Or at least the 1400 series. Not sure about 9500. IPO server edition is the way forward though, with the 500 V2 serving only as a gateway. I’d imagine this is impractical for small businesses.
But, to Keyset’s point I don’t believe there is a purely TDM system left. Maybe XBlue if you count them.
Interesting that's about it - probably no more new TDM systems. Also re: XBlue, a company I worked for previously that specialized in Iwatsu systems sold a small system with the Iwatsu name on it. Don't recall the model, but it was actually an XBlue system, I believe it could only be programmed from the attendant phone with various menus on the screen, don't think there was a serial interface. While there's probably still a fair amount of Iwatsu systems out there, I believe phone and other hardware ceased production in 2008 or 2009, after a tsunami is said to have damaged a main factory enough to shut it down.
And re: NEC - I recall working on NEC Patrician phones and KSUs in the late 1970s. They, like the Iwatsu key systems of the era, didn't use the standard 25 pair color code with their phones.
And re: Mitel - I heard they acquired Unify, which is what Siemens telecom became.