Hi, I love what you are doing and I am very impressed so far!
One thing that my team would really benefit from would be the ability to add single channel guests (for one-off projects for example).
Is this something you are considering?
Also on a personal note I am also quite happy to try out features and will be installing the new releases when they are released, so if you want a hand with some user testing do let me know!
Thanks
David
Thanks David! Sorry for the delayed response - we have considered a feature like that, and would like to implement it at some point. It isn’t planned for the immediate future, but we’ve heard similar requests from a couple other users. If we continue to get feedback from the community about this, we may move it up in the roadmap.
Anyone interested in this feature can also upvote the request on our uservoice page here.
As for testing, we love getting feedback from the community on any issues they find! We prepare a release candidate that is available for testing before the actual release comes out, which can be found here: https://github.com/mattermost/platform/releases. Our next release candidate should be out in a couple of weeks.
Agreed! I just gave it three votes.
This is the ONE HOPE that brought me to find Mattermost.
So-far, (from what I can tell) it’s not possible in Slack without paying a fortune; to have clients join and have no-access to view other parties is key. And it looks like it’s not possible here yet either. 
Hi @pixelmelter, appreciate your feedback, upvotes welcome on this feature.