The only thing I could find is https://wiki.freepascal.org/Free_Pascal#Lazarus_and_the_Free_Pascal_Compiler where is written:
...
I seem to remember there being a compatibility matrix/table in the wiki at one time. Still unable to locate it though

Thank you for the link, I guess it is better than nothing.
Thought probably right it sounds a bit strict. Usually the mentioned FPC version is the minimal required version and because FPC also usually supports at least one release of backwards compatibility that should /in theory/ also work. That is, without introduced breaking changes (which should happen fewer and fewer by each new release). A similar construction also applies to/for Lazarus. It is just that the version you prefer are so far between that there are issues.
A hindsight advice: try to keep older written applications (at least a little) up to date and check for breaking changes with every release (and accommodate for that in your code when necessary).
Hence the advice from my previous post to install an older Linux distro in something like a VM and install the older versions of FPC/Lazarus, e.g. in order to try update old (incompatible) code step-by-step. Another possible solution is bite the bullit and update in one go.
I did not know, that installing older Lazarus / FPC versions is such a problem after some time (on Linux).
Unfortunately there are many breaking changes in the Linux runtime. Probably argued with a "if you strictly followed the guidelines you should not have any problems" but alas, here we are.
The only advise to give, I guess, is try and find the lowest FPC/Lazarus version available that is able to run for you (either VM or otherwise with an older version of your distro) and try if that these are still able to build and run your code and try to work your way up from there.
You are right in that the choices of FPCUpDeluxe to mix and match different FPC and Lazarus version numbers is perhaps a bit misleading as only certain combinations actually work and older versions do not actually build anymore on newer distributions. It would also be a tremendous amount of work to figure this out for all supported platforms and make something like FPCUpDeluxe act according to that information.
It might perhaps be obvious for someone that is familiar with FPC/Lazarus that f.e. Lazarus 4.0RC3 does not compile with FPC 2.0 (many new features have been introduced to the compiler since then and which Lazarus relies on) but someone new might perhaps be puzzled by it.