Coming more than six months after Ubuntu 20.04.2, the Ubuntu 20.04.3 LTS point release is here with updated kernel and graphics stacks from the Ubuntu 21.04 (Hirsute Hippo) release. More precisely, it’s powered by the HWE (Hardware Enablement) Linux 5.11 kernel series and uses the latest Mesa 21.0 graphics stack.
As usual, the Linux 5.11 HWE kernel included in the Ubuntu 20.04.3 LTS point release is intended for newer installations where the hardware is not fully supported by the stock kernel. As such, if you’re using Ubuntu 20.04 LTS with the stock kernel, you won’t receive the newer kernel when performing an upgrade.