2012 or earlier.
14+ years of support for a device is decent. I would imagine there's all kind of technical debt in there that would require more maintenance than revenue.
Looks my Kindle Voyage from 2014 just made it past the cut-off-date. Which is good, because my wife has just discovered its advantages. Still works like a charm and gives maybe a week of service without recharging.
I suspect the models that are phased out now can't handle current encryption schemes, which would be a good reason to get rid of those legacy devices from their perspective.
I have one that I use to rip kindle unlimited books. That is why they are getting rid of them. I can send the book to my old keyboard kindle and then pull it off into calibre and it's been unencrypted. The newer devices receive the books encrypted and no one has cracked it yet.
Thought so. Last time I looked into decryption with Calibre was many years ago. I thought they'd have that cracked by now.
My 2014 Voyage went through a firmware update a short time after I got it. Decryption was trivial before and impossible afterwards.
Some of them are old enough to have operated on the HSDPA WCDMA system. That's been gone for years.
Mine is 3G, so I think that was HSDPA/UMTS iirc?:
Kindle Voyage 3G, 15,2 cm (6 Zoll) hochauflösendes Display (300 ppi) mit integriertem intelligenten Frontlicht, PagePress-Sensoren, Gratis 3G + WLAN EUR 249,00 Verkauft von: Amazon EU S.a.r.L.
We're only using the net functionality on WiFi anyway.