The question was asked here "Which version (of SAP) shall I download to work with book "Schrödinger programmiert ABAP""
Surely the answer is that it's all of them until the wave function collapses.
Don't we face the Schrödinger's paradox almost everyday?
The program is simultaneously working & not working at the same time.
Since this situation is common, irrespective of the SAP release, IMO the OP can download any version.
I'm pretty much sure that SAP Leonardo won't be able to crack this paradox :-/
Well, following In-memory computing is Quantum computing, I guess. So, after the conversion is before the conversion. According to the PAM, End of Mainstream Maintenance for S/4HANA 1610 is 31.12.2021.
Here kitty, kitty. I have some treats for you...
The real paradox is why would anyone want to spend time learning ABAP at home these days? Some kind of ancient language feti$h?
This would be more fun: http://www.worldofspectrum.org/ZX81BasicProgramming/