Fix legacy client detection

PROTOCOL.md

@@ -22,11 +22,11 @@ Clients must send a register command, reset command or login command before send
   - Register an account. A valid email address must be provided.
   - Usernames must contain at least one non-numeric character.
 
-- `registerjson <client name> <email> <username> <password>`
+- `registerjson <client> <email> <username> <password>`
   - Register an account and enable JSON formatted responses.
   - All client applications should use the `registerjson` command to register, as JSON 
 formatted responses are more easily parsed by computers.
-  - The name of the client must be specified.
+  - The client field is specified as follows: `example-client-v1.2.3/en`
   - Aliases: `rj`
 
 - `resetpassword <email>`
@@ -37,11 +37,11 @@ formatted responses are more easily parsed by computers.
   - Log in. A random username is assigned when none is provided.
   - Usernames must contain at least one non-numeric character.
 
-- `loginjson <client name> [username] [password]`
+- `loginjson <client> [username] [password]`
   - Log in and enable JSON formatted responses.
   - All client applications should use the `loginjson` command to log in, as JSON 
 formatted responses are more easily parsed by computers.
-  - The name of the client must be specified.
+  - The client field is specified as follows: `example-client-v1.2.3/en`
   - Aliases: `lj`
 
 - `password <old> <new>`

pkg/server/client.go

@@ -347,18 +347,32 @@ func logClientRead(msg []byte) {
 }
 
 func legacyClient(clientName []byte) bool {
+	// Strip language.
+	slash := bytes.IndexByte(clientName, '/')
+	if slash != -1 {
+		clientName = clientName[:slash]
+	}
+
+	// Split by hyphens.
 	split := bytes.Split(clientName, []byte("-"))
 	if len(split) == 0 {
 		return true
-	} else if !bytes.Equal(split[0], []byte("boxcars")) {
+	}
+
+	// Only Boxcars requires legacy support.
+	if !bytes.Equal(split[0], []byte("boxcars")) {
 		return false
 	}
+
+	// Parse version information.
 	last := split[len(split)-1]
 	lastSplit := bytes.Split(last, []byte("."))
 	if len(lastSplit) != 3 {
 		return true
 	}
 	major, minor := parseInt(lastSplit[0]), parseInt(lastSplit[1])
+
+	// Boxcars releases before v1.4.0 require legacy support.
 	return major < 1 || (major == 1 && minor < 4)
 }