Fix missing group members on 2.5 clients

README.md

@@ -10,8 +10,12 @@ The plugin is compiled to Java 8 bytecode and runs on newer JVMs.
 The server negotiates the protocol generation during the existing voice-chat
 handshake and stores it with that player's 16-byte secret. The UDP path then
 uses AES-CBC for 2.5 clients and AES-GCM for 2.6 clients. Shared packet layouts
-are passed through the existing 2.6 voice routing. The fork changes only the
-per-client cipher selection and compatibility-version acceptance.
+are passed through the existing 2.6 voice routing. State messages are sent on
+the channel names expected by each client generation, so 2.5 clients receive
+their player and group-member updates as well. For compatibility 18 the server
+maps `voicechat:state` and `voicechat:states` to the older
+`voicechat:player_state` and `voicechat:player_states` channels. When a player
+leaves, it sends the disconnected state because 2.5 has no remove-state packet.
 
 The Bukkit plugin source and API source are in `source/bukkit/` and
 `source/api/`. The cipher and compatibility changes are in the regular source