Upgrading concerns

Absolute noob here. I have 6 clusters to upgrade to the latest 3.9.1.1 (community ed.).

4 cluster with 3 nodes each are running v.3.2.0.
The other 2 clusters of 2 nodes each are running citrusleaf 2.7.26.
Each cluster is split into two, east and west, with xdr in between.

I’m pretty sure it will be a rolling upgrade, so heartbeat compatibility will need to be accounted for when upgrading citrusleaf. I’ll also need to do a clean install for both version.

Are there any caveats to note when uninstalling? Will i need to clean up any logs saved configs or tmp or cached data?

Thanks in advance, any and all help is greatly appreciated.