Asking for a friend… 
I can’t seem to be able to find the docker image through synology’s GUI, and I’m a bit reluctant to play around with the shell. I don’t want / have zero interest in a native syno package. Docker has been a real eye-opener and I don’t want to move back.
I guess it can be installed with a docker command on the shell, but I’d rather have a “clean” solution where I can manage everything from the synology interface. At least there I know what I’m doing, and I’m actively trying to move away from fiddling with stuff when I’m home, I get plenty of that at work.
So maybe it’s a bit paradoxial that I want to play with a test version, but there’s so many good things in there that I want to try 
So, am I doing something wrong to find the docker image? If it matters: it’s a DS1813+, DSM 6.2-23739 Update 2 (latest as of this moment).