Mattermost

Antimatter

Mattermost started paywalling features it used to give away and sells the rest by the seat. Antimatter is the fork with the licence checks pulled out: SSO, LDAP, no nag screens, no invoice.

“Unfortunately, after a few disappointments at a previous company actually trying (and giving up) to buy a licence, and after their latest actions, which I could only call backstabs (paywalling previously available features, putting arbitrary limits that previously didn't exist, or recently adding nag screens to push people into either buying their licence or just away from their platform altogether), I've ended up fed up with their BS and started to work on a fork.”