Robert Miller replied to the topic 'How to update Stellarmate ?' in the forum. 7 months ago

Oh yes. Got to this webpage

and scroll down until you see the header Nightly Builds. You want to add the repository for the nightly builds as shown, then apt-update, then install the programs (kstars-bleeding, indi-full).

I think, but am not sure, you need to remove the stable repository in order for this to all work. To remove the stable repository, type
apt-add-repository remove ppa:mutlaqja/ppa