is it possible to update PHD2 within the Astroberry environment by building PHD2 from Git without messing up the system? The apt update/upgrade procedure is always a bit outdated (still PHD 2.6.7).
The latest PHD2 version 2.6.9 has been just pushed to Astroberry repository.
If you want to follow bleeding edge version you can compile from sources as indicated by Patrick.
If you choose /usr/local as destination directory at compilation, you keep separate version, not conflicting with existing version. Up to you to decide