NAS Sinology 209j in the middle of 2009. Even that time it had very limited hardware, therefore I was not surprised that it did not get a major version software update and is frozen with DSM 4.X.
Nevertheless, the recent update (security fixes) I got in the beginning of 2015. In 6 years!
I would like all my gadgets would be supported this way.
And guess what NAS manufacturer was first in the list when I decided to do an upgrade? You got it!
Read more about NASes and backups.