Then, for classic Amigas/68k, some other developers made 3.1.4 and 3.2 based on 3.1 plus some 68k reimplementations of some of the 4.x parts as well as some other improvements
For 3.1.4, they weren’t “other developers”, they were pretty much the same ones that also worked on 3.5 and 3.9, most of the key components also came from 3.9 just as much as from 3.1 directly, only a few came via 4.x. The only missing 3.9 components were all the ReAction classes and resource.library, and software relying on these, essentially all OS3.9 Reaction based prefs programs. Oh, and HDToolBox (and hdwrench.library) by Joan Dow. With 3.2 ReAction classes and various other components/features were ported/reimplemented back from OS 4.x, and some developers replaced in the process. Noteworthy is that key developer and one if the two original initiative takers of 3.1.4 and arguably the most influential OS 3.2 developer (you know who), left the OS team long before its release, and is now seen arguing with some of the current developers (the usual very opinionated suspects) over certain choices done for the OS 3.2 release. So I would argue that the REAL end-of-line OS release for A2000 (and the other 68k systems) is currently on the hard drive of ThoR
And this brings us back to what Amiga is REALLY about - drama! - arguing, whining, bickering, blaming, entitlement, huge egos, besserwissers, splitting, forking, hacking, patching…
