You can updates the Astroberry using:
sudo apt update
sudo apt upgrade
Notes on preinstalled Software
(In alphabetical order)
ASTAP is not part of the usual package repositories, you therefore have to download and update it yourself. It can be found at this sourceforge page. Download the „armhf“ version and install it using dpkg. Information on databases can be found on ASTAP’s homepage
Cartes Du Ciel, SkyCharts, CCDciel
CdC is updated using the package repository offered by the original developer and therefore covered by apt upgrade. This is included as package repository in the Astroberry image, see here for the procedure that needs to be followed.