diff --git a/adapters/discord/src/message.ts b/adapters/discord/src/message.ts
index 23723c6c..c030d822 100644
--- a/adapters/discord/src/message.ts
+++ b/adapters/discord/src/message.ts
@@ -88,7 +88,8 @@ export class DiscordMessageEncoder<C extends Context = Context> extends MessageE
     const { filename, data, mime } = await this.bot.ctx.http.file(attrs.src || attrs.url, attrs)
     const form = new FormData()
     const value = new Blob([data], { type: mime })
-    form.append('file', value, attrs.file || filename)
+    // https://discord.com/developers/docs/reference#uploading-files
+    form.append('files[0]', value, attrs.file || filename)
     form.append('payload_json', JSON.stringify(payload))
     return this.post(form)
   }
@@ -300,7 +301,15 @@ export class DiscordMessageEncoder<C extends Context = Context> extends MessageE
     } else if (type === 'audio') {
       await this.sendAsset('file', attrs, {
         ...this.addition,
-        content: this.buffer.trim(),
+        content: '',
+        attachments: [
+          {
+            waveform: '', // base64 encoded bytearray representing a sampled waveform
+            id: 0,
+            duration_secs: attrs.duration ?? 0,
+          },
+        ],
+        flags: Message.Flag.IS_VOICE_MESSAGE,
       })
       this.buffer = ''
     } else if (type === 'author') {
diff --git a/adapters/discord/src/types/message.ts b/adapters/discord/src/types/message.ts
index 56789f7b..676bb755 100644
--- a/adapters/discord/src/types/message.ts
+++ b/adapters/discord/src/types/message.ts
@@ -134,6 +134,10 @@ export namespace Message {
     LOADING = 1 << 7,
     /** this message failed to mention some roles and add their members to the thread */
     FAILED_TO_MENTION_SOME_ROLES_IN_THREAD = 1 << 8,
+    /** this message will not trigger push and desktop notifications */
+    SUPPRESS_NOTIFICATIONS = 1 << 12,
+    /** this message is a voice message */
+    IS_VOICE_MESSAGE = 1 << 13,
   }
 
   /** https://discord.com/developers/docs/resources/channel#message-reference-object-message-reference-structure */