Upgrade UCP and DTR

we want to update our environment. But I’m not completely sure how.
Here our current version:
CentOS 7.0
Docker engine 1.11cs
UCP 1.1.1
DTR 2.0.3

We want to go to the latest version of UCP (2.2.2) and DTR (2.3.2)

What I understood is that we need a newer CentOS version (7.1 or 7.2) and the docker enterprise engine (17.06)
After that I would upgrade UCP to 2.2.2 directly, I didn’t find any hint that I need to install other versions first.
And at last I would upgrade DTR first to 2.1 -> 2.2 -> 2.3.2.

Is this correct?

No one? Please help!