Debian is the second-oldest Linux distro still being maintained. According to the Wikipedia page for it, the first version was released on September 15, 1993. I recently installed Debian as a virtual machine, followed by Devuan, which is a fork of Debian. I then installed Linux Mint Debian Edition (LMDE) to verify that it used the Cinnamon desktop environment.
The Debian Project maintains three branches: Stable, testing and unstable. Some distros are based on the stable branch and some on testing. I have yet to hear of anything based on the unstable branch.
Debian 10 is the current stable branch, code-named “buster”. The current testing branch is code-named “bullseye”. The unstable branch is always code-named “sid”. When the testing branch is changed to stable, it will be Debian 11. I have no idea what the new testing branch will be code-named.
Apparently, Debian doesn’t update desktop environments until the next testing branch is created. During installation, I selected multiple desktop environments, so I could examine them later. After the installation was complete, I examined the Cinnamon, KDE Plasma and Xfce desktop environments. I also examined the Openbox and Fluxbox (which I had to install) window managers, and that’s all I have to say about that.
Cinnamon was outdated, and it didn’t have any of the Linux Mint icons (and I didn’t expect it to). KDE Plasma was outdated. Xfce was up-to-date. To have an updated Cinnamon, the Linux Mint Cinnamon Edition is the best way to get it. To have an updated KDE Plasma, either KDE Neon or Kubuntu is the way to go.
According to the Wikipedia page for it, the first version of Devuan was released on May 3, 2016. It was forked from Debian because a lot of Linux developers didn’t like the systemd initialization system. Devuan offers older initialization systems, but not systemd.
Other than that, and a cleaner installation process, it’s virtually the same as Debian. I don’t think I need to go into further detail.
While the first version of Linux Mint Cinnamon was released in 2009, LMDE was released in 2010. LMDE is based on the Debian stable branch. The other editions are based on Ubuntu, which itself is based on the Debian testing branch.
While Debian is way friendlier than Slackware, it still isn’t something I would recommend for new users. That is, unless you’re a purist or something. I have a contact in India who won’t use anything else.
If you want an up-to-date desktop environment, regardless of which one, you should pursue a distro that uses it as a flagship desktop environment. For KDE Neon, it’s KDE Plasma. All the flavors of Ubuntu are kept as up-to-date as the main one, Ubuntu, which uses the GNOME desktop environment. Linux Mint keeps all of its editions as up-to-date as Cinnamon, which includes Mate and Xfce.