Just for other who might hit this thread:
https://openmodelica.org/forum/default- … ak-v1-13-2

Why not an Appimage?
From the user point of you it is easier to install.
(I did not manage to install the flatpack and the compilation from source is not so easy with all the dependencies to fulfil).
So an Appimage (instead of deb and rpm) with alla the dependencies included and in a known and tested version should be better for this kind of software.
Do you agree?

There are docker images of OpenModelica. They work just fine even with GUIs according to my testing

As far as I remember, AppImage is only 1 application - OpenModelica is many different applications and depends on having things like entire development toolchains installed.

I think that Flatpak should be easier to maintain than AppImage because you have better control of the dependencies (IMHO). Compared to docker, I think you get better integration with the desktop.

If it were integrated into flathub, you would receive directly the binary. But I don't have the time to do it.

I have updated the github repository, changing everything to YAML (instead of JSON manifest, which are easier to read and comment). I have corrected a few problems preventing from compiling.

I have added bundles, which enable  installing without needing to compile anything. @Xwang1976, it would be create if you could try to install from them (you might need to fulfill the prerrequisites.