Texlive old install support

[TeXnician]

Hi,

> A real problem is that each year I have to move to the latest tex live
> distribution; which inevitably breaks the building of documents based on older
> packages.  

Why should it break? Docker supports versioning (tagging). So you could have a
tag latest point to the latest TeX Live but provide tags for older releases.
Have a look at the images of the Island of TeX:
  https://gitlab.com/islandoftex/images/texlive
They provide latest and historical releases.

> Philosophically, this is a serious problem.  There are many old documents which
> will require expert intervention to create if the build tools move this much
> every year, and the old tools do not work.

When using tagging the user could fetch a versioned (read TL year) image.
Because the ISO images of old releases do not change there would be no broken
documents.

> Can there be a long term maintenance policy for some versions of texlive?
>  Leaving an archive to 3rd parties does not seem reasonable, especially if those
> builds just fail after one year…

What's missing from the ISO images that are provided on the mirrors? They are a
complete snapshot of the software at that time.

Greetings, T.