The following things come to my mind:
- Bigger updates from experimental builds ; For example, the Nutrition Update or the Vehicle update would have been worthy of a post.
- (good) new videos about CDDA / Let’s plays of it.
- Noteworthy new stories/art about CDDA
- Big or important bugfixes
- News about the next stable version (whenever THAT comes out)
- Infos about other roguelikes people might enjoy
- Tips & Tricks for newer players (or even a beginners guide)
- News about planned features
- Funny screenshots of stuff happening in cdda
Of course, depending on how you want to run the Group, some of those options might not be a good idea. Depending on the people in the group, too many updates might also give them a reason to leave the group.
Still, a lot of people who are playing CDDA are actually not active in the forum, so you could provide an alternative source of information with your group to those people - if you’re able to get them to join that is.