From Minecraft Wiki
June 20, 2009
- Allow players to send most admin commands via stdin.
- Added chat throttling.
- Players who spam the chat will get muted for eight seconds.
- Added movement throttling.
- The server will not process more than a single move command per tick.
- Stand still to catch up if it's lagging.
- This is the maximum number of connections per IP to the server.
- Defaults to three.
- Fixed a client crash bug on chat.
- "Client 0.0.19a is up, a server update is required" – The Word of Notch, June 20, 2009.