Document v2 changes

IMPLEMENTATION.md

@@ -10,6 +10,31 @@ How to write your own client. The Java client will serve as an example implement
     * Hybi 10
     * Hixie 76
     * Hixie 75
+
+## Changes v1.3 -> v2.0 
+With the release of v2.0 many unnecessary ops were removed:
+
+* `connect`
+* `disconnect`
+* `validationRes`
+* `isConnectedRes`
+* `validationReq`
+* `isConnectedReq`
+* `sendWS`
+
+With Lavalink 1.x the server had the responsibility of handling Discord VOICE_SERVER_UPDATEs as well as its own internal ratelimiting.
+This remote handling makes things unnecessarily complicated and adds a lot og points where things could go wrong. 
+One problem we noticed is that since JDAA is unaware of ratelimits on the bot's gateway connection, it would keep adding
+to the ratelimit queue to the gateway. With this update this is now the responsibility of the Lavalink client or the 
+Discord client.
+
+A voice connection is now initiated by forwarding a `voiceUpdate` (VOICE_SERVER_UPDATE) to the server. When you want to
+disconnect or move to a different voice channel you must send Discord a new VOICE_STATE_UPDATE. If you want to move your
+connection to a new Lavalink server you can simply send the VOICE_SERVER_UPDATE to the new node, and the other node
+will be disconnected by Discord.
+
+Depending on your Discord library, it may be possible to take advantage of the library's OP 4 handling. For instance,
+the JDA client takes advantage of JDA's websocket write thread to send OP 4s for connects, disconnects and reconnects.
 
 ## Protocol
 ### Opening a connection