I've posted an updated version of this table in an answer below. The below table is outdated, provided for context so the question makes sense. Below is a table which sums up my knowledge: So, I assume these are also transitional, but I've no idea what IDE or compiler they appear in, or what caveats they come with. This misconception is mostly due to the fact that, the official Git repo, and Xcode Release Notes don't mention them at all. I was under the assumption that 3.2 was the last version of 3, for use in migrating to 4, 4.2, and 5. Today, I discovered that Swift 3.3 and 3.4 exist.

Yet, still, certain facts slip through, whether by me being blindsided, or by Apple being very quiet about them. I enjoy the language and follow it as closely as I can. Please, describe what is the correct flow of update to latest Swift in general, and how this works with some of pods that are not updating to the latest Swift each year.I develop apps in Swift for a living. What about my Workspace? My target builds fine without errors and warnings, I'm not sure why it tells me about conversion? Shouldn't it tell an exact line in the file with code instead? Regardings Pods, it is clear that Cocoapods will fix that, so np. What exactly does that mean? Should I change it to Swift 4 instead? Or that's just like minimum version that I have to write code according to?

However, I see that the Swift version in target settings is still set to Swift 3.2. Since I'm using Cocoapods, I obviously updated all pods to their latest versions, which I believe is correct behavior.

Now I upgraded Xcode 9, which AFAIU supports Swift 4. My project has been started under Xcode 8 and Swift 3.2. I'm kinda new to Swift (less than 1 full year), and I'm not sure how to update to latest Swift within the new Xcode each year.

Latest version of swift and xcode