Ubuntu has put out the latest point release of its stable version, or the fourth bugfix of 20.04. The main difference will be visible in new installs: a clean install of 20.04.4 – for example on some new hardware – will get kernel version 5.13 from 21.10 “Impish Indri”, which came out after 20.04.3 last August. However, if you already have “Focal Fossa” installed and just run a normal update, you’ll get 20.04.4.

Source: LXer – Canonical puts out last update to Ubuntu 20.04