Ok, there is a way I can see, but it will be painful.
I had have a machine and it was running.... Stretch and an early version of NR.
I wanted to install a new bit of code, but time bit me in the bottom and I couldn't.
So I rebuilt the machine, ground up.
and now I have NR 4.0.9 and Dashboard 2.x installed.
That ain't gonna work with the old flow/s and the OLD dashboard nodes.
Options?
Ok, I could install the older dashboard, import the flows then migrate the nodes to the newer ones.
I don't believe so. Install D1 since it runs in parallel anyway. Then take your time to migrate to something newer - maybe even avoid future similar issues by migrating to UIBUILDER
Either way, you can take your time. I doubt D1 will disappear any time soon.
Honestly, I prefer to reinstall from scratch when I can. It tends to end up with a much cleaner installation and fewer issues. I see this as an advantage of using small, cheap(ish) devices, harder to do on a full server unless you have a spare.