Sorry for the basic question, if an answer or information already exists, please point me to it.
Why would I chose to use Neo4j Community 4.1.xx over 3.5.xx and why does the 3.5.xx continue to be developed? (I know 3.5.xx will no longer be supported after Nov. '21.) I'm looking to learn why the 2 different versions continue to be developed at the same time, at least for now.
Major versions (3.x to 4.x) are rare, and happen only after several years. This often accompanies many new features, and dropping of deprecated features. The time and effort for migration to a new major version is also more intensive than between minor releases or patch releases.
There are also several customers relying on features that are no longer present in 4.x, and we want to make sure we support them on 3.5.x until we have solutions for them in 4.x.
Keep in mind also that by "support", we mean that we will offer bug fixes in the form of patch releases on 3.5.x. We will not be developing new features for 3.x, that's done.
So in terms of looking to the future, go for 4.x, unless you have to interact with a system running on a lower version.