AppImage fails to run on Ubuntu 21.04

Wanted to test the AppImage on a fresh Ubuntu 21.04 today but it failed:

/tmp/.mount_KStarstGS39g//usr/bin/kstars: error while loading shared libraries: libstellarsolver.so.1: cannot open shared object file: No such file or directory

So I installed libstellarsolver (wasn't this supposed to be included already in the bundle?)

Then it failed again:

ERROR: ld.so: object 'libapprun_hooks.so' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored.
/tmp/.mount_KStarsyV57vA//usr/bin/kstars: error while loading shared libraries: libcfitsio.so.8: cannot open shared object file: No such file or directory

I had libcfitsio9 installed on 21.04 which is the package available for it officially.