diff --git a/app/media/service.py b/app/media/service.py
index b848bf9..a2d7bfc 100644
--- a/app/media/service.py
+++ b/app/media/service.py
@@ -23,6 +23,8 @@ ALLOWED_MIME_TYPES = {
     "video/webm",
     "audio/mpeg",
     "audio/ogg",
+    "audio/mp4",
+    "audio/x-m4a",
     "audio/webm",
     "audio/wav",
     "application/pdf",
diff --git a/docs/core-checklist-status.md b/docs/core-checklist-status.md
index 8997bdb..4c5732e 100644
--- a/docs/core-checklist-status.md
+++ b/docs/core-checklist-status.md
@@ -23,7 +23,7 @@ Legend:
 14. Delivery Status - `DONE` (sent/delivered/read + reconnect reconciliation after backend restarts)
 15. Typing Realtime - `DONE` (typing start/stop + recording voice start/stop + recording video start/stop in circle-video send flow)
 16. Media & Attachments - `DONE` (upload/preview/download/gallery; sticker/GIF inline media no longer opens photo viewer on click)
-17. Voice Messages - `PARTIAL` (record/send/play/seek + global speed 1x/1.5x/2x; recorder uses improved mime priority for better duration metadata; audio store tracks duration via `durationchange/seekable` fallback; websocket send/recorder stop race on fast chat switch is guarded; UX still being polished)
+17. Voice Messages - `PARTIAL` (record/send/play/seek + global speed 1x/1.5x/2x; recorder uses improved mime priority for better duration metadata; backend media allowlist includes `audio/mp4`/`audio/x-m4a`; audio store tracks duration via `durationchange/seekable` fallback; websocket send/recorder stop race on fast chat switch is guarded; UX still being polished)
 18. Circle Video Messages - `PARTIAL` (send/play present, recording UX basic)
 19. Stickers - `PARTIAL` (web sticker picker with preset pack + favorites)
 20. GIF - `PARTIAL` (web GIF picker with Tenor search + preset fallback + favorites)