diff --git a/src/ackTracker.js b/src/ackTracker.js
index 630baca..643479d 100644
--- a/src/ackTracker.js
+++ b/src/ackTracker.js
@@ -24,6 +24,7 @@ function registerSend(messageId, chatId, filename) {
     ack: 0,
     notifiedStuck: false
   })
+  console.log(`[ack] track ${messageId} (${filename} → ${chatId})`)
 }
 
 function handleAck(messageId, ack) {
@@ -31,7 +32,10 @@ function handleAck(messageId, ack) {
   const entry = sends.get(messageId)
   if (!entry) return
   if (ack > entry.ack) entry.ack = ack
-  if (ack >= 2) sends.delete(messageId) // delivered; nothing left to track
+  if (ack >= 2) {
+    sends.delete(messageId) // delivered; nothing left to track
+    console.log(`[ack] delivered ack=${ack} ${messageId} (${entry.filename})`)
+  }
 }
 
 function stuckEntries() {