Are there any plans to make the ISO available for this version?
Thanks.
No.
It was never supported by either Ubuntu nor Canonical.
It was produced as a by-product of a no-longer run procedure, as you'll note here
Canonical and the Ubuntu project never officially supported the mini.iso ; it was produced as a by-product of building the debian-installer. As the Ubuntu Server image now uses
subiquity
, the build process that built mini.iso is no longer used, thus why this installation media is now old.