Disco is out today, and I just realize this. Of course, releases which are too old lacks some sort of features to support new software, and developers can either implement workarounds or it is simply not possible. However, Cosmic it not really that old at the time of writing, but newest packages are not available for it. There are countless examples:
lzipis available on Cosmic as 1.20-1, and on Disco as 1.21-3vlcis available on Cosmic as 3.0.4-2build1, and on Disco as 3.0.6-1gimpis available on Cosmic as 2.10.6-3, and on Disco as 2.10.8-2)- ...
Is there any technical difficulty, or just because Canonical wants to push people to update their OS?