By default, 3.6.3 is installed right now. That is more recent than 3.6.2.
I’m trying to pin it to 3.6.2 now; however, it seems to install 3.6.3 on me. I believe I am following the syntax so I’d expect the correct subversion, but I am not as well versed with R and Binder to come up with what I missing here.
UPDATE: I don’t think I’m missing something. I think the packages installed will be tied the MRAN snapshot date I specify but that the patch release version of R cannot right not be specified beyond 3.6. In other words no specific subversions of R beyond 3.5, 3.6 or 3.7, etc. See here. And even that I’m not 100% sure since I haven’t tested 3.5 recently because you said 3.6 is good.
3.6.3 is even better for me — the use I intend to do for this is educational, rather than “proper” work, so being a couple of release behind is not the end of the world… I can see your point though (even in your UPDATE) — but to confirm, 3.6 is good enough for this, so I’m happy with that! 
Thanks
I am still getting 3.6.3 currently but it may be because that snapshot date and the 3.6 don’t match?
Currently it uses 3.6.3. There is no way to specify a specific release patch of 3.6. You get what Binder has as the current patch release version of 3.6 when you don’t specify 3.5 or 3.4.
I’m trying to create a separate JupyterHub cluster for an upcoming workshop that requires using RStudio sessions rather than using R kernel in JupyterHub. Since a proper multi-user RStudio setup can currently only be implemented via commercial version of RStudio Server and because I want to take advantage from JupyterHub’s convenient authentication mechanisms (and container-based session isolation), I was working hard to setup a z2jh-based JupyterHub cluster similarly to how Binder enables such setup. get-vidmate.com instasave.onl
@feedtaleone You’ve got a couple of suspicious looking links at the end of your previous post. Are those intentional?