My team uses Slack and want to replace it with a self-hosted open source alternative.
Absolute requirements:
- Open source (server and ALL clients)
- Self-hostable
- Rock-solid native apps for Android and iOS
- Web app available
- Channels (I mean I can create multiple chat rooms, for instance for each project)
- Ability to post new items from an RSS/Atom feed in a channel as they come
- All content invisible to outsiders
- For each message, see sender and time
- Channel notifications, that can be configured (eg. mute this channel)
- Messages can be edited after sending, but are marked with time of last modification
- Can see messages that have been exchanged when I was not connected
- History fully searchable from any of the apps
Bonus:
- Threaded discussion