Decide the minimal required versions of MATLAB and Octave for Dynare 6

We need to decide the minimal required versions of MATLAB and Octave for Dynare 6.

Dynare 5 requires at least MATLAB R2014a and Octave 5 (at the source code level for the latter).

Since Dynare 5 was released in January 2022, it means that upon release we were supporting 8 years of MATLAB (R2014a to R2021b); and we are currently supporting 10 years of MATLAB.

If we were to apply the same policy for Dynare 6, that would mean requiring R2016a. But we could also be more aggressive, which would bring some benefits (see the MATLAB versions page):

• R2016b would allow us to remove all calls to bsxfun, and also to drop the JSONlab toolbox under contrib/ (provided that we also require Octave 7)
• R2018a would allow us to ship only one flavour of the MEX files (since that version introduced an ABI break)
• R2018b would allow us to use double quoted strings (and thus stop worrying about using single quotes everywhere)

And requiring R2019a would mean moving to 5-years window of MATLAB releases supported, which is already quite a lot.

I think we should go for at least R2016b, and maybe even R2018b.

For Octave, we already require Octave 6 in unstable. I would be inclined to require Octave 7, because that would allow us to drop JSONlab (if we also require MATLAB R2016b). My only concern is that Ubuntu 22.04 LTS ships with Octave 6 (so that may affect you @wmutschl); however note that Ubuntu 24.04 LTS will be released shortly after Dynare 6, and it will include Octave 8.

Waiting for your thoughts on this. We should also ask our institutional users about their constraints.