diff --git a/gencapdefs.py b/gencapdefs.py
index 2daf59bd..0dab5b3e 100644
--- a/gencapdefs.py
+++ b/gencapdefs.py
@@ -77,7 +77,7 @@ CAPDEFS = [
     ),
     CapDef(
         identifier="LabeledResponse",
-        name="draft/labeled-response",
+        name="draft/labeled-response-0.2",
         url="https://ircv3.net/specs/extensions/labeled-response.html",
         standard="draft IRCv3",
     ),
diff --git a/irc/caps/defs.go b/irc/caps/defs.go
index 6a691bbc..4092bb2f 100644
--- a/irc/caps/defs.go
+++ b/irc/caps/defs.go
@@ -53,7 +53,7 @@ const (
 	// https://ircv3.net/specs/extensions/invite-notify-3.2.html
 	InviteNotify Capability = iota
 
-	// LabeledResponse is the draft IRCv3 capability named "draft/labeled-response":
+	// LabeledResponse is the draft IRCv3 capability named "draft/labeled-response-0.2":
 	// https://ircv3.net/specs/extensions/labeled-response.html
 	LabeledResponse Capability = iota
 
@@ -135,7 +135,7 @@ var (
 		"echo-message",
 		"extended-join",
 		"invite-notify",
-		"draft/labeled-response",
+		"draft/labeled-response-0.2",
 		"draft/languages",
 		"oragono.io/maxline-2",
 		"message-tags",
diff --git a/irc/responsebuffer.go b/irc/responsebuffer.go
index 794254c0..e651cd4a 100644
--- a/irc/responsebuffer.go
+++ b/irc/responsebuffer.go
@@ -212,16 +212,24 @@ func (rb *ResponseBuffer) flushInternal(final bool, blocking bool) error {
 	}
 
 	useLabel := rb.session.capabilities.Has(caps.LabeledResponse) && rb.Label != ""
-	// use a batch if we have a label, and we either currently have 0 or 2+ messages,
+	// use a batch if we have a label, and we either currently have 2+ messages,
 	// or we are doing a Flush() and we have to assume that there will be more messages
 	// in the future.
-	useBatch := useLabel && (len(rb.messages) != 1 || !final)
+	startBatch := useLabel && (1 < len(rb.messages) || !final)
 
-	// if label but no batch, add label to first message
-	if useLabel && !useBatch && len(rb.messages) == 1 && rb.batchID == "" {
-		rb.messages[0].SetTag(caps.LabelTagName, rb.Label)
-	} else if useBatch {
+	if startBatch {
 		rb.sendBatchStart(blocking)
+	} else if useLabel && len(rb.messages) == 0 && rb.batchID == "" && final {
+		// ACK message
+		message := ircmsg.MakeMessage(nil, rb.session.client.server.name, "ACK")
+		message.SetTag(caps.LabelTagName, rb.Label)
+		if rb.session.capabilities.Has(caps.ServerTime) {
+			message.SetTag("time", time.Now().UTC().Format(IRCv3TimestampFormat))
+		}
+		rb.session.SendRawMessage(message, blocking)
+	} else if useLabel && len(rb.messages) == 1 && rb.batchID == "" && final {
+		// single labeled message
+		rb.messages[0].SetTag(caps.LabelTagName, rb.Label)
 	}
 
 	// send each message out