diff --git a/.openclaw-sync/source.json b/.openclaw-sync/source.json
index 887a56460..514d9ff7b 100644
--- a/.openclaw-sync/source.json
+++ b/.openclaw-sync/source.json
@@ -1,5 +1,5 @@
 {
   "repository": "openclaw/openclaw",
-  "sha": "f44759073b3cf2937847660e4ee12d220627b207",
-  "syncedAt": "2026-04-25T05:41:24.376Z"
+  "sha": "537a8e25ed5dbfff1ea3802435b3a7a019c4f2c3",
+  "syncedAt": "2026-04-25T05:46:56.800Z"
 }
diff --git a/docs/channels/signal.md b/docs/channels/signal.md
index eedd78154..39346f43e 100644
--- a/docs/channels/signal.md
+++ b/docs/channels/signal.md
@@ -208,6 +208,7 @@ Groups:
 - Outbound text is chunked to `channels.signal.textChunkLimit` (default 4000).
 - Optional newline chunking: set `channels.signal.chunkMode="newline"` to split on blank lines (paragraph boundaries) before length chunking.
 - Attachments supported (base64 fetched from `signal-cli`).
+- Voice-note attachments use the `signal-cli` filename as a MIME fallback when `contentType` is missing, so audio transcription can still classify AAC voice memos.
 - Default media cap: `channels.signal.mediaMaxMb` (default 8).
 - Use `channels.signal.ignoreAttachments` to skip downloading media.
 - Group history context uses `channels.signal.historyLimit` (or `channels.signal.accounts.*.historyLimit`), falling back to `messages.groupChat.historyLimit`. Set `0` to disable (default 50).