Add message clear option

docs/image-mode-technical.md

@@ -5,8 +5,9 @@
 Image mode mirrors the voice on-demand architecture exactly:
 
 - **Control plane (text messages):**
-  - `IE1:` image envelope announces image availability in chat.
+  - `IE2:` image envelope announces image availability in chat.
-  - `IR1:` direct fetch request asks sender to stream image fragments.
+- **Control plane (raw binary request):**
+  - Binary image fetch request (same raw route as image fragments).
 - **Data plane (raw binary packets):**
   - `ImagePacket` binary payload streamed via `cmdSendRawData` / `pushRawData`.
 
@@ -17,8 +18,8 @@ pixels are fetched on demand when the user taps the image bubble.
 
 - `lib/utils/image_message_parser.dart`
   - `ImagePacket` (binary fragment format)
-  - `ImageEnvelope` (`IE1`)
+  - `ImageEnvelope` (`IE2`)
-  - `ImageFetchRequest` (`IR1`)
+  - `ImageFetchRequest` (binary)
   - `fragmentImage()` — split compressed bytes into packets
   - `reassembleImage()` — join received fragments into bytes
 - `lib/screens/messages_tab.dart`
@@ -27,7 +28,7 @@ pixels are fetched on demand when the user taps the image bubble.
   - Reassembly sessions, outgoing cache, deferred serving
   - Outgoing sessions also registered as complete incoming sessions for immediate local display
 - `lib/providers/app_provider.dart`
-  - Incoming routing for `IE1`, `IR1`, binary `0x49` packets
+  - Incoming routing for `IE2`, binary image fetch requests, binary `0x49` packets
 - `lib/widgets/messages/image_message_bubble.dart`
   - Square cover thumbnail (up to 256 px); tap-to-load for received images;
     progress ring during fetch; full-screen `InteractiveViewer` on tap
@@ -39,52 +40,52 @@ pixels are fetched on demand when the user taps the image bubble.
 
 ## 3. Wire Formats
 
-### 3.1 Image Envelope (`IE1`)
+### 3.1 Image Envelope (`IE2`)
 
-Prefix: `IE1:` + colon-delimited payload
+Prefix: `IE2:` + colon-delimited compact payload (base36 numeric fields)
 
 Fields:
 
 | Field        | Type   | Description                                    |
 |--------------|--------|------------------------------------------------|
-| `sid`        | string | 8 hex chars (4 bytes), session ID              |
+| `sid`        | string | base36 token for 32-bit session ID             |
-| `fmt`        | int    | `ImageFormat.id` (0 = AVIF, 1 = JPEG)         |
+| `fmt`        | base36 | `ImageFormat.id` (0 = AVIF, 1 = JPEG)         |
-| `total`      | int    | Fragment count (1..255)                        |
+| `total`      | base36 | Fragment count (1..255)                        |
-| `w`          | int    | Actual image width after compression (pixels)  |
+| `w`          | base36 | Actual image width after compression (pixels)  |
-| `h`          | int    | Actual image height after compression (pixels) |
+| `h`          | base36 | Actual image height after compression (pixels) |
-| `bytes`      | int    | Total compressed size in bytes                 |
+| `bytes`      | base36 | Total compressed size in bytes                 |
 | `senderKey6` | string | 12 hex chars (6 bytes sender prefix)           |
-| `ts`         | int    | Unix timestamp (seconds)                       |
+| `ts`         | base36 | Unix timestamp (seconds)                       |
-| `ver`        | int    | Protocol version (currently `1`)               |
 
 Compact format:
 
 ```text
-IE1:{sid}:{fmt}:{total}:{w}:{h}:{bytes}:{senderKey6}:{ts}:{ver}
+IE2:{sid}:{fmt}:{total}:{w}:{h}:{bytes}:{senderKey6}:{ts}
 ```
 
 Example (256×171 landscape image, 14 fragments):
 
 ```text
-IE1:deadbeef:0:14:256:171:2100:aabbccddeeff:1700000000:1
+IE2:a:0:e:74:4r:1mc:aabbccddeeff:s44we8
 ```
 
-Note: `w` and `h` reflect the actual post-compression dimensions, which preserve
+Note: `sid` is base36 on wire and expands to 8-hex internally.
+`w` and `h` reflect the actual post-compression dimensions, which preserve
 the source aspect ratio (contain within the configured max size).
 
-### 3.2 Image Fetch Request (`IR1`)
+### 3.2 Image Fetch Request (binary)
 
-Same structure as `VR1`:
+Binary payload format:
 
 ```text
-IR1:{sid}:{want}:{requesterKey6}:{ts}:{ver}
+[magic=0x69][sid:4B][flags:1B][requesterKey6:6B][ts:4B][missingCount:1B][missingIndices...]
 ```
 
 | Field            | Value                    |
 |------------------|--------------------------|
-| `want`           | `a` (= "all fragments")  |
+| `flags`          | bit0=1 => request missing indices, else all |
-| `requesterKey6`  | 12 hex chars             |
+| `requesterKey6`  | 6-byte requester key prefix |
-| `ver`            | `1`                      |
+| `ts`             | unix timestamp seconds (u32) |
 
 ### 3.3 Raw Image Packet (data plane)
 
@@ -151,16 +152,16 @@ only the shorter axis is padded — no cropping occurs.
 7. Envelope sent via normal message path:
    - Channel: `sendChannelMessage`
    - Direct: `sendTextMessage`
-8. Local placeholder message added (`IE1:` text, `deliveryStatus.sending`).
+8. Local placeholder message added (`IE2:` text, `deliveryStatus.sending`).
 
 ## 6. Incoming Flow (Receive)
 
-### 6.1 `IE1` envelope received
+### 6.1 `IE2` envelope received
 
 `AppProvider` calls `imageProvider.registerEnvelope()` and adds the message to
 chat.  The bubble shows a grey square placeholder with a download icon.
 
-### 6.2 `IR1` request received
+### 6.2 Binary image fetch request received
 
 `AppProvider` treats it as control-plane only (not added to chat):
 
@@ -194,7 +195,7 @@ When `cacheOutgoingSession()` is called it also writes all fragments into
 - **Complete session**: `AspectRatio(1.0)` → `AvifImage.memory(fit: cover)`
   square thumbnail; tap → full-screen `InteractiveViewer` with fade transition.
 - **Incomplete/missing**: grey square placeholder with download icon;
-  tap → sends `IR1` fetch request.
+  tap → sends binary fetch request.
 - **Loading**: circular progress indicator showing `received/total` count.
 - **Error**: broken-image icon.
 
@@ -212,7 +213,8 @@ Image bubbles and Message Technical Details show an **estimated transmit time**
 The estimate is airtime-based (LoRa packet model), not just compressed image size:
 
 - Source inputs:
-  - `total` fragments and `bytes` from `IE1` envelope
+  - `total` fragments and `bytes` from `IE2` envelope
+  - all numeric envelope values are decoded from base36
   - `pathLen` from message metadata
   - current radio params from `deviceInfo`: `radioBw`, `radioSf`, `radioCr`
 - Per-fragment payload model:
@@ -270,10 +272,10 @@ sequenceDiagram
   A->>A: Compress: contain resize → grayscale → PNG → AVIF
   A->>A: Fragment into ≤152B packets
   A->>A: Cache outgoing + populate local session (immediate display)
-  A->>M: Send IE1 envelope (actual w×h, fragment count)
+  A->>M: Send IE2 envelope (actual w×h, fragment count)
-  M->>B: Deliver IE1
+  M->>B: Deliver IE2
   B->>B: Render grey placeholder bubble
-  B->>A: Tap → send IR1 fetch request
+  B->>A: Tap → send binary fetch request
   A->>B: Stream binary ImagePackets
   B->>B: Reassemble fragments
   B->>B: Display AVIF image (cover thumbnail)

docs/voice-mode-technical.md

@@ -5,8 +5,9 @@
 Voice mode uses a **two-plane architecture**:
 
 - **Control plane (text messages):**
-  - `VE1:` voice envelope announces voice availability in chat.
+  - `VE2:` voice envelope announces voice availability in chat.
-  - `VR1:` direct fetch request asks sender to stream voice payload.
+- **Control plane (raw binary request):**
+  - Binary voice fetch request (same raw route as voice packets).
 - **Data plane (raw binary packets):**
   - `VoicePacket` payload streamed via `cmdSendRawData` and received through `pushRawData`.
 
@@ -16,73 +17,58 @@ This design avoids broadcasting full voice payloads to channels/rooms. Chat carr
 
 - `lib/utils/voice_message_parser.dart`
   - `VoicePacket` (legacy text + binary packet format)
-  - `VoiceEnvelope` (`VE1`)
+  - `VoiceEnvelope` (`VE2`)
-  - `VoiceFetchRequest` (`VR1`)
+  - `VoiceFetchRequest` (binary)
 - `lib/screens/messages_tab.dart`
   - Capture/encode voice, cache encoded packets, send envelope only
 - `lib/providers/voice_provider.dart`
   - Reassembly/playback sessions
   - Outgoing session cache + deferred serving
 - `lib/providers/app_provider.dart`
-  - Incoming routing for `VE1` and `VR1`
+  - Incoming routing for `VE2` and binary voice fetch requests
   - Handles raw packet ingestion
 - `lib/widgets/messages/voice_message_bubble.dart`
   - Play behavior (immediate play if complete, otherwise fetch + auto-play)
 - `lib/providers/messages_provider.dart`
-  - Message-level voice detection (`VE1` + legacy `V:`)
+  - Message-level voice detection (`VE2` + legacy `V:`)
 - `lib/services/message_storage_service.dart`
   - Persists `isVoice` and `voiceId`
 
 ## 3. Wire Formats
 
-### 3.1 Voice Envelope (`VE1`)
+### 3.1 Voice Envelope (`VE2`)
 
-Prefix: `VE1:` + colon-delimited compact payload
+Prefix: `VE2:` + colon-delimited compact payload (base36 numeric fields)
 
 Fields:
 
-- `sid` (string, 8 hex chars): session ID
+- `sid` (string): base36 token for 32-bit session ID
-- `mode` (int): codec mode ID (`VoicePacketMode.id`)
+- `mode` (base36): codec mode ID (`VoicePacketMode.id`)
-- `total` (int): packet count (1..255)
+- `total` (base36): packet count (1..255)
-- `durMs` (int): estimated duration in ms
+- `durS` (base36): estimated duration in seconds
 - `senderKey6` (string, 12 hex chars): sender public-key prefix (6 bytes)
-- `ts` (int): unix timestamp seconds
+- `ts` (base36): unix timestamp seconds
-- `ver` (int): protocol version (currently `1`)
+
+`sid` is base36 on wire and expands to 8-hex internally.
 
 Compact format:
 
 ```text
-VE1:{sid}:{mode}:{total}:{durMs}:{senderKey6}:{ts}:{ver}
+VE2:{sid}:{mode}:{total}:{durS}:{senderKey6}:{ts}
 ```
 
 Example:
 
 ```text
-VE1:deadbeef:1:4:3200:aabbccddeeff:1700000000:1
+VE2:a:1:4:4:aabbccddeeff:s44we8
 ```
 
-### 3.2 Voice Fetch Request (`VR1`)
+### 3.2 Voice Fetch Request (binary)
 
-Prefix: `VR1:` + colon-delimited compact payload
+Binary payload format:
-
-Fields:
-
-- `sid` (string, 8 hex chars): requested session
-- `want` (string): currently `a` (compact token for `all`)
-- `requesterKey6` (string, 12 hex chars): requester key prefix
-- `ts` (int): unix timestamp seconds
-- `ver` (int): protocol version (`1`)
-
-Compact format:
 
 ```text
-VR1:{sid}:{want}:{requesterKey6}:{ts}:{ver}
+[magic=0x72][sid:4B][flags:1B][requesterKey6:6B][ts:4B][missingCount:1B][missingIndices...]
-```
-
-Example:
-
-```text
-VR1:deadbeef:a:112233445566:1700000010:1
 ```
 
 ### 3.3 Raw Voice Packet (data plane)
@@ -102,18 +88,18 @@ Binary payload structure:
 2. Each chunk is codec2-encoded into `VoicePacket` objects.
 3. Packets are cached in `VoiceProvider` outgoing cache (TTL 15 min).
 4. Sender inserts local voice placeholder message (`isVoice=true`, `voiceId=sessionId`).
-5. Sender sends one envelope (`VE1`) through normal message path:
+5. Sender sends one envelope (`VE2`) through normal message path:
    - channel/room: `sendChannelMessage`
    - direct: `sendTextMessage`
 6. **No raw audio packets are sent during initial send.**
 
 ## 5. Incoming Routing
 
-### 5.1 `VE1` envelope received
+### 5.1 `VE2` envelope received
 
 `AppProvider` marks message as voice (`isVoice`, `voiceId`) and adds it to chat.
 
-### 5.2 `VR1` request received
+### 5.2 Binary voice fetch request received
 
 `AppProvider` treats it as control-plane only:
 
@@ -132,8 +118,8 @@ In `VoiceMessageBubble`:
 
 - If session already complete: play immediately.
 - If incomplete/missing:
-  1. Resolve sender contact (message sender prefix or `VE1.senderKey6` fallback)
+  1. Resolve sender contact (message sender prefix or `VE2.senderKey6` fallback)
-  2. Send direct `VR1` fetch request
+  2. Send direct binary fetch request
   3. Show requesting state in UI
   4. Auto-play when session becomes complete
 
@@ -170,10 +156,9 @@ Parser validation enforces:
 - strict hex lengths for IDs and key prefixes
 - valid mode range
 - valid packet counts and duration bounds
-- fixed protocol version (`ver == 1`)
+- compact base36 numeric fields in envelope/request
-- `VR1.want` token `a` (internally normalized to `all`)
+- Binary request flags specify `all` or `missing` indices.
-
+- Request payload includes `requesterKey6` to resolve return route.
-`VR1` handling verifies sender prefix matches `requesterKey6` to reduce spoofing risk.
 
 ## 10. Transmit Time Estimate (UI)
 
@@ -182,7 +167,8 @@ Voice bubbles and Message Technical Details show an **estimated transmit time**
 The estimate is airtime-based (LoRa packet model), not file-duration-only:
 
 - Source inputs:
-  - `packetCount` and `durationMs` from `VE1` envelope, or
+  - `packetCount` and `durationMs` from `VE2` envelope, or
+  - numeric envelope values decoded from base36
   - actual received `VoicePacket.codec2Data.length` bytes when local session packets exist
   - `pathLen` from message metadata
   - current radio params from `deviceInfo`: `radioBw`, `radioSf`, `radioCr`
@@ -223,7 +209,7 @@ Fallback defaults are used when radio params are unavailable: `SF10`, `BW250kHz`
 ## 12. Backward Compatibility
 
 - Legacy `V:` text packet parsing is still supported.
-- Message voice detection accepts both new `VE1` and legacy `V:` formats.
+- Message voice detection accepts `VE2` and legacy `V:` formats.
 
 ## 13. High-Level Sequence
 
@@ -235,10 +221,10 @@ sequenceDiagram
 
   A->>A: Record + encode voice packets
   A->>A: Cache session packets (TTL 15m)
-  A->>M: Send VE1 envelope
+  A->>M: Send VE2 envelope
-  M->>B: Deliver VE1
+  M->>B: Deliver VE2
   B->>B: Render voice bubble (metadata only)
-  B->>A: Send VR1 request on Play
+  B->>A: Send binary fetch request on Play
   A->>B: Stream raw VoicePacket packets
   B->>B: Reassemble session
   B->>B: Auto-play when complete

lib/providers/app_provider.dart

@@ -57,8 +57,11 @@ class AppProvider with ChangeNotifier {
   static const Duration _packetRetryDelay = Duration(milliseconds: 1200);
   static const int _maxPacketRetryAttempts = 4;
   final Map<String, String> _voiceSessionSenderKey6 = {};
+  final Map<String, String> _imageSessionSenderKey6 = {};
   final Map<String, Timer> _voiceMissingRetryTimers = {};
   final Map<String, int> _voiceMissingRetryAttempts = {};
+  final Map<String, Completer<void>> _voiceFragmentAckWaiters = {};
+  final Map<String, Completer<void>> _imageFragmentAckWaiters = {};
   Timer? _packetCaptureFlushTimer;
   String? _lastPersistedPacketSignature;
   bool _isPersistingPacketCapture = false;
@@ -404,6 +407,24 @@ class AppProvider with ChangeNotifier {
             payload: payload,
           );
         };
+    voiceProvider.waitForFragmentAckCallback = ({
+      required sessionId,
+      required index,
+      timeout = const Duration(seconds: 8),
+    }) => _waitForVoiceFragmentAck(
+      sessionId: sessionId,
+      index: index,
+      timeout: timeout,
+    );
+    imageProvider.waitForFragmentAckCallback = ({
+      required sessionId,
+      required index,
+      timeout = const Duration(seconds: 8),
+    }) => _waitForImageFragmentAck(
+      sessionId: sessionId,
+      index: index,
+      timeout: timeout,
+    );
 
     // When a contact is received from BLE
     connectionProvider.onContactReceived = (contact) {
@@ -540,62 +561,6 @@ class AppProvider with ChangeNotifier {
         }
       }
 
-      // Voice control plane: request sender to stream raw voice packets.
-      final voiceFetchRequest = VoiceFetchRequest.tryParseText(
-        enrichedMessage.text,
-      );
-      if (voiceFetchRequest != null) {
-        final senderPrefix = enrichedMessage.senderPublicKeyPrefix;
-        if (senderPrefix == null) {
-          debugPrint(
-            '⚠️ [AppProvider] Voice fetch request without sender prefix',
-          );
-          return;
-        }
-        final senderPrefixHex = senderPrefix
-            .take(6)
-            .map((b) => b.toRadixString(16).padLeft(2, '0'))
-            .join('');
-        if (senderPrefixHex.toLowerCase() !=
-            voiceFetchRequest.requesterKey6.toLowerCase()) {
-          debugPrint('⚠️ [AppProvider] Voice fetch requester key mismatch');
-          return;
-        }
-        final requester = contactsProvider.findContactByPrefix(senderPrefix);
-        if (requester == null) {
-          debugPrint(
-            '⚠️ [AppProvider] Voice fetch requester contact not found',
-          );
-          messagesProvider.logSystemMessage(
-            text:
-                'Cannot fetch voice: requester contact is unknown. Add/sync contacts first.',
-            level: 'warning',
-          );
-          return;
-        }
-        if (requester.outPathLen > _maxDirectPayloadHops) {
-          debugPrint(
-            '⚠️ [AppProvider] Voice fetch requester too far: ${requester.outPathLen} hops',
-          );
-          messagesProvider.logSystemMessage(
-            text:
-                'Cannot fetch voice for ${requester.advName}: message is too far (${requester.outPathLen} hops, max $_maxDirectPayloadHops).',
-            level: 'warning',
-          );
-          return;
-        }
-        unawaited(
-          voiceProvider.serveSessionTo(
-            sessionId: voiceFetchRequest.sessionId,
-            requester: requester,
-            requestedIndices: voiceFetchRequest.want == 'missing'
-                ? voiceFetchRequest.missingIndices.toSet()
-                : null,
-          ),
-        );
-        return;
-      }
-
       // Check if message is a drawing broadcast
       if (DrawingMessageParser.isDrawingMessage(enrichedMessage.text)) {
         debugPrint('🎨 [AppProvider] Drawing message received, parsing...');
@@ -665,61 +630,12 @@ class AppProvider with ChangeNotifier {
         return;
       }
 
-      // Image fetch request (IR1): requester asks us to stream image fragments.
-      final imageFetchRequest = ImageFetchRequest.tryParse(
-        enrichedMessage.text,
-      );
-      if (imageFetchRequest != null) {
-        final senderPrefix = enrichedMessage.senderPublicKeyPrefix;
-        if (senderPrefix != null) {
-          final senderPrefixHex = senderPrefix
-              .take(6)
-              .map((b) => b.toRadixString(16).padLeft(2, '0'))
-              .join('');
-          if (senderPrefixHex.toLowerCase() ==
-              imageFetchRequest.requesterKey6.toLowerCase()) {
-            final requester = contactsProvider.findContactByPrefix(
-              senderPrefix,
-            );
-            if (requester != null) {
-              if (requester.outPathLen > _maxDirectPayloadHops) {
-                debugPrint(
-                  '⚠️ [AppProvider] Image fetch requester too far: ${requester.outPathLen} hops',
-                );
-                messagesProvider.logSystemMessage(
-                  text:
-                      'Cannot fetch image for ${requester.advName}: message is too far (${requester.outPathLen} hops, max $_maxDirectPayloadHops).',
-                  level: 'warning',
-                );
-                return;
-              }
-              unawaited(
-                imageProvider.serveSessionTo(
-                  sessionId: imageFetchRequest.sessionId,
-                  requester: requester,
-                  requestedIndices: imageFetchRequest.want == 'missing'
-                      ? imageFetchRequest.missingIndices.toSet()
-                      : null,
-                ),
-              );
-            } else {
-              debugPrint(
-                '⚠️ [AppProvider] Image fetch requester contact not found',
-              );
-              messagesProvider.logSystemMessage(
-                text:
-                    'Cannot fetch image: requester contact is unknown. Add/sync contacts first.',
-                level: 'warning',
-              );
-            }
-          }
-        }
-        return; // IR1 is control-plane only; not displayed in chat
-      }
-
       // Image envelope (IE1): announce image availability.
       final imageEnvelope = ImageEnvelope.tryParse(enrichedMessage.text);
       if (imageEnvelope != null) {
+        _imageSessionSenderKey6[imageEnvelope.sessionId] = imageEnvelope
+            .senderKey6
+            .toLowerCase();
         imageProvider.registerEnvelope(imageEnvelope);
         messagesProvider.addMessage(
           enrichedMessage,
@@ -800,8 +716,99 @@ class AppProvider with ChangeNotifier {
     };
 
     // When raw binary data is received (PUSH_CODE_RAW_DATA 0x84)
+    // Magic 0x72 'r' = voice fetch request; 0x69 'i' = image fetch request.
     // Magic 0x56 'V' = voice packet; magic 0x49 'I' = image packet.
     connectionProvider.onRawDataReceived = (payload, snrRaw, rssiDbm) {
+      final voiceFetchRequest = VoiceFetchRequest.tryParseBinary(payload);
+      if (voiceFetchRequest != null) {
+        final requester = contactsProvider.findContactByPrefixHex(
+          voiceFetchRequest.requesterKey6,
+        );
+        if (requester == null) {
+          debugPrint(
+            '⚠️ [AppProvider] Voice fetch requester contact not found (binary)',
+          );
+          messagesProvider.logSystemMessage(
+            text:
+                'Cannot fetch voice: requester contact is unknown. Add/sync contacts first.',
+            level: 'warning',
+          );
+          return;
+        }
+        if (requester.outPathLen > _maxDirectPayloadHops) {
+          debugPrint(
+            '⚠️ [AppProvider] Voice fetch requester too far: ${requester.outPathLen} hops',
+          );
+          messagesProvider.logSystemMessage(
+            text:
+                'Cannot fetch voice for ${requester.advName}: message is too far (${requester.outPathLen} hops, max $_maxDirectPayloadHops).',
+            level: 'warning',
+          );
+          return;
+        }
+        unawaited(
+          voiceProvider.serveSessionTo(
+            sessionId: voiceFetchRequest.sessionId,
+            requester: requester,
+            requestedIndices: voiceFetchRequest.want == 'missing'
+                ? voiceFetchRequest.missingIndices.toSet()
+                : null,
+          ),
+        );
+        return;
+      }
+
+      final imageFetchRequest = ImageFetchRequest.tryParseBinary(payload);
+      if (imageFetchRequest != null) {
+        final requester = contactsProvider.findContactByPrefixHex(
+          imageFetchRequest.requesterKey6,
+        );
+        if (requester == null) {
+          debugPrint(
+            '⚠️ [AppProvider] Image fetch requester contact not found (binary)',
+          );
+          messagesProvider.logSystemMessage(
+            text:
+                'Cannot fetch image: requester contact is unknown. Add/sync contacts first.',
+            level: 'warning',
+          );
+          return;
+        }
+        if (requester.outPathLen > _maxDirectPayloadHops) {
+          debugPrint(
+            '⚠️ [AppProvider] Image fetch requester too far: ${requester.outPathLen} hops',
+          );
+          messagesProvider.logSystemMessage(
+            text:
+                'Cannot fetch image for ${requester.advName}: message is too far (${requester.outPathLen} hops, max $_maxDirectPayloadHops).',
+            level: 'warning',
+          );
+          return;
+        }
+        unawaited(
+          imageProvider.serveSessionTo(
+            sessionId: imageFetchRequest.sessionId,
+            requester: requester,
+            requestedIndices: imageFetchRequest.want == 'missing'
+                ? imageFetchRequest.missingIndices.toSet()
+                : null,
+          ),
+        );
+        return;
+      }
+
+      final voiceAck = VoiceFragmentAck.tryParseBinary(payload);
+      if (voiceAck != null) {
+        _completeVoiceFragmentAck(voiceAck.sessionId, voiceAck.index);
+        return;
+      }
+
+      final imageAck = ImageFragmentAck.tryParseBinary(payload);
+      if (imageAck != null) {
+        _completeImageFragmentAck(imageAck.sessionId, imageAck.index);
+        return;
+      }
+
       if (ImagePacket.isImageBinary(payload)) {
         final frag = ImagePacket.tryParseBinary(payload);
         if (frag == null) return;
@@ -812,6 +819,7 @@ class AppProvider with ChangeNotifier {
           width: session?.width ?? 0,
           height: session?.height ?? 0,
         );
+        _sendImageFragmentAck(frag);
         return;
       }
 
@@ -820,6 +828,7 @@ class AppProvider with ChangeNotifier {
       if (pkt == null) return;
       debugPrint('🎙️ [AppProvider] Binary voice packet received: $pkt');
       final justComplete = voiceProvider.addPacket(pkt);
+      _sendVoiceFragmentAck(pkt);
       _scheduleVoiceMissingRetry(pkt.sessionId, justComplete: justComplete);
       // Insert or update the placeholder message in the chat list
       _handleIncomingVoicePacket(pkt, justComplete: justComplete);
@@ -1209,15 +1218,18 @@ class AppProvider with ChangeNotifier {
       missingIndices: missing,
       requesterKey6: requesterKey6,
       timestampSec: DateTime.now().millisecondsSinceEpoch ~/ 1000,
-      version: 1,
+      version: 2,
     );
 
-    final sent = await connectionProvider.sendTextMessage(
+    try {
-      contactPublicKey: sender.publicKey,
+      await connectionProvider.sendRawVoicePacket(
-      text: request.encodeText(),
+        contactPath: sender.outPath,
-      contact: sender,
+        contactPathLen: sender.outPathLen,
+        payload: request.encodeBinary(),
       );
-    if (!sent) return;
+    } catch (_) {
+      return;
+    }
 
     _voiceMissingRetryAttempts[sessionId] = attempt + 1;
     _voiceMissingRetryTimers[sessionId]?.cancel();
@@ -1266,6 +1278,102 @@ class AppProvider with ChangeNotifier {
     messagesProvider.addMessage(placeholder, contactLookup: (_) => '');
   }
 
+  String _fragmentAckKey(String sessionId, int index) => '$sessionId:$index';
+
+  Future<bool> _waitForVoiceFragmentAck({
+    required String sessionId,
+    required int index,
+    Duration timeout = const Duration(seconds: 8),
+  }) async {
+    final key = _fragmentAckKey(sessionId, index);
+    final completer = Completer<void>();
+    _voiceFragmentAckWaiters[key] = completer;
+    try {
+      await completer.future.timeout(timeout);
+      return true;
+    } catch (_) {
+      if (_voiceFragmentAckWaiters[key] == completer) {
+        _voiceFragmentAckWaiters.remove(key);
+      }
+      return false;
+    }
+  }
+
+  void _completeVoiceFragmentAck(String sessionId, int index) {
+    final key = _fragmentAckKey(sessionId, index);
+    final completer = _voiceFragmentAckWaiters.remove(key);
+    if (completer != null && !completer.isCompleted) {
+      completer.complete();
+    }
+  }
+
+  Future<bool> _waitForImageFragmentAck({
+    required String sessionId,
+    required int index,
+    Duration timeout = const Duration(seconds: 8),
+  }) async {
+    final key = _fragmentAckKey(sessionId, index);
+    final completer = Completer<void>();
+    _imageFragmentAckWaiters[key] = completer;
+    try {
+      await completer.future.timeout(timeout);
+      return true;
+    } catch (_) {
+      if (_imageFragmentAckWaiters[key] == completer) {
+        _imageFragmentAckWaiters.remove(key);
+      }
+      return false;
+    }
+  }
+
+  void _completeImageFragmentAck(String sessionId, int index) {
+    final key = _fragmentAckKey(sessionId, index);
+    final completer = _imageFragmentAckWaiters.remove(key);
+    if (completer != null && !completer.isCompleted) {
+      completer.complete();
+    }
+  }
+
+  void _sendVoiceFragmentAck(VoicePacket packet) {
+    final senderKey6 = _voiceSessionSenderKey6[packet.sessionId];
+    if (senderKey6 == null) return;
+    final sender = _resolveContactByPrefixHex(senderKey6);
+    if (sender == null) return;
+    if (sender.outPathLen < 0 || sender.outPathLen > _maxDirectPayloadHops) {
+      return;
+    }
+    unawaited(
+      connectionProvider.sendRawVoicePacket(
+        contactPath: sender.outPath,
+        contactPathLen: sender.outPathLen,
+        payload: VoiceFragmentAck(
+          sessionId: packet.sessionId,
+          index: packet.index,
+        ).encodeBinary(),
+      ),
+    );
+  }
+
+  void _sendImageFragmentAck(ImagePacket fragment) {
+    final senderKey6 = _imageSessionSenderKey6[fragment.sessionId];
+    if (senderKey6 == null) return;
+    final sender = _resolveContactByPrefixHex(senderKey6);
+    if (sender == null) return;
+    if (sender.outPathLen < 0 || sender.outPathLen > _maxDirectPayloadHops) {
+      return;
+    }
+    unawaited(
+      connectionProvider.sendRawVoicePacket(
+        contactPath: sender.outPath,
+        contactPathLen: sender.outPathLen,
+        payload: ImageFragmentAck(
+          sessionId: fragment.sessionId,
+          index: fragment.index,
+        ).encodeBinary(),
+      ),
+    );
+  }
+
   // Removed _syncMessages() - messages are automatically synced via PUSH_CODE_MSG_WAITING events
   // The ConnectionProvider's onMessageWaiting callback handles automatic message fetching
 

lib/providers/image_provider.dart

@@ -68,6 +68,12 @@ class ImageProvider with ChangeNotifier {
     required Uint8List payload,
   })?
   sendRawPacketCallback;
+  Future<bool> Function({
+    required String sessionId,
+    required int index,
+    Duration timeout,
+  })?
+  waitForFragmentAckCallback;
 
   ImageProvider() {
     _restore();
@@ -229,11 +235,25 @@ class ImageProvider with ChangeNotifier {
         continue;
       }
       try {
+        final ackFuture = waitForFragmentAckCallback?.call(
+          sessionId: sessionId,
+          index: fragment.index,
+          timeout: const Duration(seconds: 8),
+        );
         await sendRawPacketCallback!(
           contactPath: requester.outPath,
           contactPathLen: requester.outPathLen,
           payload: fragment.encodeBinary(),
         );
+        if (ackFuture != null) {
+          final acked = await ackFuture;
+          if (!acked) {
+            debugPrint(
+              '⚠️ [ImageProvider] ACK timeout for $sessionId#${fragment.index}',
+            );
+            return false;
+          }
+        }
       } catch (e, st) {
         debugPrint('❌ [ImageProvider] Serve error for $sessionId: $e\n$st');
         return false;

lib/providers/voice_provider.dart

@@ -69,6 +69,12 @@ class VoiceProvider with ChangeNotifier {
     required Uint8List payload,
   })?
   sendRawPacketCallback;
+  Future<bool> Function({
+    required String sessionId,
+    required int index,
+    Duration timeout,
+  })?
+  waitForFragmentAckCallback;
 
   final Map<String, _OutgoingVoiceSession> _outgoingSessions = {};
 
@@ -198,11 +204,25 @@ class VoiceProvider with ChangeNotifier {
         continue;
       }
       try {
+        final ackFuture = waitForFragmentAckCallback?.call(
+          sessionId: sessionId,
+          index: packet.index,
+          timeout: const Duration(seconds: 8),
+        );
         await sendRawPacketCallback!(
           contactPath: requester.outPath,
           contactPathLen: requester.outPathLen,
           payload: packet.encodeBinary(),
         );
+        if (ackFuture != null) {
+          final acked = await ackFuture;
+          if (!acked) {
+            debugPrint(
+              '⚠️ [VoiceProvider] ACK timeout for $sessionId#${packet.index}',
+            );
+            return false;
+          }
+        }
       } catch (e, st) {
         debugPrint(
           '❌ [VoiceProvider] Failed serving packet for $sessionId: $e\n$st',

lib/screens/settings_screen.dart

@@ -621,6 +621,46 @@ class _SettingsScreenState extends State<SettingsScreen> {
     );
   }
 
+  Future<void> _clearMessages() async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: const Text('Clear Messages'),
+        content: const Text(
+          'This will permanently delete all stored messages. Are you sure?',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context, false),
+            child: Text(AppLocalizations.of(context)!.cancel),
+          ),
+          TextButton(
+            onPressed: () => Navigator.pop(context, true),
+            style: TextButton.styleFrom(foregroundColor: Colors.red),
+            child: Text(AppLocalizations.of(context)!.clear),
+          ),
+        ],
+      ),
+    );
+
+    if (confirmed != true || !mounted) return;
+
+    final messagesProvider = Provider.of<MessagesProvider>(
+      context,
+      listen: false,
+    );
+    messagesProvider.clearMessages();
+
+    if (!mounted) return;
+
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(
+        content: Text('All messages cleared'),
+        backgroundColor: Colors.orange,
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -694,6 +734,15 @@ class _SettingsScreenState extends State<SettingsScreen> {
             trailing: const Icon(Icons.chevron_right),
             onTap: () => _showLanguageDialog(),
           ),
+          ListTile(
+            leading: const Icon(Icons.delete_sweep, color: Colors.red),
+            title: const Text(
+              'Clear Messages',
+              style: TextStyle(color: Colors.red),
+            ),
+            subtitle: const Text('Delete all stored message history'),
+            onTap: _clearMessages,
+          ),
           const Divider(),
 
           // Voice Settings Section

lib/utils/image_message_parser.dart

@@ -243,11 +243,11 @@ int _resolveBandwidthHz(int? rawBw) {
 /// Envelope announcing image availability (control plane).
 ///
 /// Text format:
-///   IE1:{sid}:{fmt}:{total}:{w}:{h}:{bytes}:{senderKey6}:{ts}:{ver}
+///   IE2:{sid}:{fmt}:{total}:{w}:{h}:{bytes}:{senderKey6}:{ts}
 /// Example:
-///   IE1:deadbeef:0:7:128:128:1050:aabbccddeeff:1700000000:1
+///   IE2:deadbeef:0:7:3k:3k:t6:aabbccddeeff:s44we8
 class ImageEnvelope {
-  static const String prefix = 'IE1:';
+  static const String _prefix = 'IE2:';
 
   final String sessionId; // 8 hex chars
   final ImageFormat format;
@@ -268,38 +268,36 @@ class ImageEnvelope {
     required this.sizeBytes,
     required this.senderKey6,
     required this.timestampSec,
-    this.version = 1,
+    this.version = 2,
   });
 
-  static bool isEnvelope(String text) => text.startsWith(prefix);
+  static bool isEnvelope(String text) => text.startsWith(_prefix);
 
   static ImageEnvelope? tryParse(String text) {
     if (!isEnvelope(text)) return null;
-    final body = text.substring(prefix.length);
+    final body = text.substring(_prefix.length);
     final parts = body.split(':');
-    if (parts.length != 9) return null;
+    if (parts.length != 8) return null;
     try {
-      final sid = parts[0];
+      final sid = _decodeSessionId(parts[0]);
-      final fmtId = int.tryParse(parts[1]);
+      final fmtId = _parseInt(parts[1], base36: true);
-      final total = int.tryParse(parts[2]);
+      final total = _parseInt(parts[2], base36: true);
-      final w = int.tryParse(parts[3]);
+      final w = _parseInt(parts[3], base36: true);
-      final h = int.tryParse(parts[4]);
+      final h = _parseInt(parts[4], base36: true);
-      final bytes = int.tryParse(parts[5]);
+      final bytes = _parseInt(parts[5], base36: true);
       final senderKey6 = parts[6];
-      final ts = int.tryParse(parts[7]);
+      final ts = _parseInt(parts[7], base36: true);
-      final ver = int.tryParse(parts[8]);
 
-      if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sid)) return null;
+      if (sid == null) return null;
       if (fmtId == null) return null;
       if (total == null || total < 1 || total > 255) return null;
       if (w == null || h == null || w < 1 || h < 1) return null;
       if (bytes == null || bytes < 1) return null;
       if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(senderKey6)) return null;
       if (ts == null || ts <= 0) return null;
-      if (ver == null || ver != 1) return null;
 
       return ImageEnvelope(
-        sessionId: sid.toLowerCase(),
+        sessionId: sid,
         format: ImageFormat.fromId(fmtId),
         total: total,
         width: w,
@@ -307,7 +305,7 @@ class ImageEnvelope {
         sizeBytes: bytes,
         senderKey6: senderKey6.toLowerCase(),
         timestampSec: ts,
-        version: ver,
+        version: 2,
       );
     } catch (_) {
       return null;
@@ -315,17 +313,21 @@ class ImageEnvelope {
   }
 
   String encode() =>
-      '$prefix${sessionId.toLowerCase()}:${format.id}:$total:$width:$height:$sizeBytes:${senderKey6.toLowerCase()}:$timestampSec:$version';
+      '$_prefix${_encodeSessionId(sessionId)}:'
+      '${_toBase36(format.id)}:${_toBase36(total)}:${_toBase36(width)}:'
+      '${_toBase36(height)}:${_toBase36(sizeBytes)}:'
+      '${senderKey6.toLowerCase()}:${_toBase36(timestampSec)}';
 }
 
 /// Direct request to fetch image fragments (control plane).
 ///
 /// Text format:
-///   IR1:{sid}:{want}:{requesterKey6}:{ts}:{ver}
+///   IR2:{sid}:{want}:{requesterKey6}:{ts}
 /// Example:
-///   IR1:deadbeef:a:aabbccddeeff:1700000010:1
+///   IR2:deadbeef:a:aabbccddeeff:s44wea
 class ImageFetchRequest {
-  static const String prefix = 'IR1:';
+  static const String _prefix = 'IR2:';
+  static const int _binaryMagic = 0x69; // 'i'
 
   final String sessionId;
   final String want; // 'all' or 'missing'
@@ -340,51 +342,89 @@ class ImageFetchRequest {
     this.missingIndices = const [],
     required this.requesterKey6,
     required this.timestampSec,
-    this.version = 1,
+    this.version = 2,
   });
 
-  static bool isRequest(String text) => text.startsWith(prefix);
+  static bool isRequest(String text) => text.startsWith(_prefix);
+  static bool isRequestBinary(Uint8List payload) =>
+      payload.isNotEmpty && payload[0] == _binaryMagic;
 
   static ImageFetchRequest? tryParse(String text) {
     if (!isRequest(text)) return null;
-    final body = text.substring(prefix.length);
+    final body = text.substring(_prefix.length);
     final parts = body.split(':');
-    if (parts.length != 5) return null;
+    if (parts.length != 4) return null;
     try {
-      final sid = parts[0];
+      final sid = _decodeSessionId(parts[0]);
       final wantToken = parts[1];
       final requesterKey6 = parts[2];
-      final ts = int.tryParse(parts[3]);
+      final ts = _parseInt(parts[3], base36: true);
-      final ver = int.tryParse(parts[4]);
       final normalizedWant = wantToken == 'a'
           ? 'all'
-          : (wantToken.startsWith('m-') ? 'missing' : wantToken);
+          : ((wantToken.startsWith('m'))
+                ? 'missing'
+                : wantToken);
 
-      if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sid)) return null;
+      if (sid == null) return null;
       final missingIndices = <int>[];
       if (normalizedWant == 'missing') {
-        final encoded = wantToken.substring(2);
+        final encoded = wantToken.substring(1);
         if (encoded.isEmpty) return null;
-        for (final raw in encoded.split(',')) {
+        missingIndices.addAll(_decodeMissingIndicesCompact(encoded));
-          final idx = int.tryParse(raw);
-          if (idx == null || idx < 0 || idx > 254) return null;
-          missingIndices.add(idx);
-        }
         if (missingIndices.isEmpty) return null;
       } else if (normalizedWant != 'all') {
         return null;
       }
       if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(requesterKey6)) return null;
       if (ts == null || ts <= 0) return null;
-      if (ver == null || ver != 1) return null;
 
       return ImageFetchRequest(
-        sessionId: sid.toLowerCase(),
+        sessionId: sid,
         want: normalizedWant,
         missingIndices: missingIndices,
         requesterKey6: requesterKey6.toLowerCase(),
         timestampSec: ts,
-        version: ver,
+        version: 2,
+      );
+    } catch (_) {
+      return null;
+    }
+  }
+
+  static ImageFetchRequest? tryParseBinary(Uint8List payload) {
+    if (!isRequestBinary(payload)) return null;
+    if (payload.length < 17) return null; // magic+sid+flags+key6+ts+count
+    try {
+      final sid = payload
+          .sublist(1, 5)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final flags = payload[5];
+      final requesterKey6 = payload
+          .sublist(6, 12)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final ts =
+          (payload[12] << 24) |
+          (payload[13] << 16) |
+          (payload[14] << 8) |
+          payload[15];
+      final missingCount = payload[16];
+      if (payload.length != 17 + missingCount) return null;
+      final wantMissing = (flags & 0x01) == 0x01;
+      final missing = <int>[];
+      for (var i = 0; i < missingCount; i++) {
+        missing.add(payload[17 + i]);
+      }
+      return ImageFetchRequest(
+        sessionId: sid,
+        want: wantMissing ? 'missing' : 'all',
+        missingIndices: missing,
+        requesterKey6: requesterKey6,
+        timestampSec: ts,
+        version: 2,
       );
     } catch (_) {
       return null;
@@ -393,10 +433,168 @@ class ImageFetchRequest {
 
   String encode() {
     final wantToken = want == 'missing' && missingIndices.isNotEmpty
-        ? 'm-${missingIndices.join(',')}'
+        ? 'm${_encodeMissingIndicesCompact(missingIndices)}'
         : (want == 'all' ? 'a' : want);
-    return '$prefix${sessionId.toLowerCase()}:$wantToken:${requesterKey6.toLowerCase()}:$timestampSec:$version';
+    return '$_prefix${_encodeSessionId(sessionId)}:$wantToken:${requesterKey6.toLowerCase()}:${_toBase36(timestampSec)}';
   }
+
+  Uint8List encodeBinary() {
+    if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionId)) {
+      throw ArgumentError.value(sessionId, 'sessionId', 'Expected 8 hex chars');
+    }
+    if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(requesterKey6)) {
+      throw ArgumentError.value(
+        requesterKey6,
+        'requesterKey6',
+        'Expected 12 hex chars',
+      );
+    }
+    final useMissing = want == 'missing' && missingIndices.isNotEmpty;
+    final missing = useMissing
+        ? missingIndices.where((v) => v >= 0 && v <= 254).toList()
+        : <int>[];
+
+    final out = Uint8List(17 + missing.length);
+    out[0] = _binaryMagic;
+    for (var i = 0; i < 4; i++) {
+      out[1 + i] = int.parse(sessionId.substring(i * 2, i * 2 + 2), radix: 16);
+    }
+    out[5] = useMissing ? 0x01 : 0x00;
+    for (var i = 0; i < 6; i++) {
+      out[6 + i] = int.parse(
+        requesterKey6.substring(i * 2, i * 2 + 2),
+        radix: 16,
+      );
+    }
+    out[12] = (timestampSec >> 24) & 0xFF;
+    out[13] = (timestampSec >> 16) & 0xFF;
+    out[14] = (timestampSec >> 8) & 0xFF;
+    out[15] = timestampSec & 0xFF;
+    out[16] = missing.length;
+    for (var i = 0; i < missing.length; i++) {
+      out[17 + i] = missing[i];
+    }
+    return out;
+  }
+}
+
+/// Per-fragment ACK for raw image payload packets.
+///
+/// Binary format:
+///   [0x6a 'j'][sessionId:4B][index:1B]
+class ImageFragmentAck {
+  static const int _binaryMagic = 0x6a; // 'j'
+
+  final String sessionId; // 8 hex chars
+  final int index; // 0..254
+
+  const ImageFragmentAck({required this.sessionId, required this.index});
+
+  static bool isImageFragmentAckBinary(Uint8List payload) =>
+      payload.length == 6 && payload[0] == _binaryMagic;
+
+  static ImageFragmentAck? tryParseBinary(Uint8List payload) {
+    if (!isImageFragmentAckBinary(payload)) return null;
+    try {
+      final sid = payload
+          .sublist(1, 5)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final idx = payload[5];
+      return ImageFragmentAck(sessionId: sid, index: idx);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  Uint8List encodeBinary() {
+    if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionId)) {
+      throw ArgumentError.value(sessionId, 'sessionId', 'Expected 8 hex chars');
+    }
+    if (index < 0 || index > 254) {
+      throw ArgumentError.value(index, 'index', 'Expected 0..254');
+    }
+    final out = Uint8List(6);
+    out[0] = _binaryMagic;
+    for (var i = 0; i < 4; i++) {
+      out[1 + i] = int.parse(sessionId.substring(i * 2, i * 2 + 2), radix: 16);
+    }
+    out[5] = index;
+    return out;
+  }
+}
+
+int? _parseInt(String token, {required bool base36}) =>
+    int.tryParse(token, radix: base36 ? 36 : 10);
+
+String _toBase36(int value) => value.toRadixString(36);
+
+String _encodeSessionId(String sessionIdHex) {
+  if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionIdHex)) {
+    throw ArgumentError.value(sessionIdHex, 'sessionIdHex', 'Expected 8 hex chars');
+  }
+  final value = int.parse(sessionIdHex, radix: 16);
+  return value.toRadixString(36);
+}
+
+String? _decodeSessionId(String token) {
+  if (!RegExp(r'^[0-9a-z]{1,7}$').hasMatch(token)) return null;
+  final value = int.tryParse(token, radix: 36);
+  if (value == null || value < 0 || value > 0xFFFFFFFF) return null;
+  return value.toRadixString(16).padLeft(8, '0');
+}
+
+String _encodeMissingIndicesCompact(List<int> indices) {
+  final sorted = indices
+      .where((v) => v >= 0 && v <= 254)
+      .toSet()
+      .toList()
+    ..sort();
+  if (sorted.isEmpty) return '';
+  final chunks = <String>[];
+  var start = sorted.first;
+  var prev = sorted.first;
+  for (var i = 1; i < sorted.length; i++) {
+    final curr = sorted[i];
+    if (curr == prev + 1) {
+      prev = curr;
+      continue;
+    }
+    chunks.add(
+      start == prev ? _toBase36(start) : '${_toBase36(start)}-${_toBase36(prev)}',
+    );
+    start = curr;
+    prev = curr;
+  }
+  chunks.add(
+    start == prev ? _toBase36(start) : '${_toBase36(start)}-${_toBase36(prev)}',
+  );
+  return chunks.join('.');
+}
+
+List<int> _decodeMissingIndicesCompact(String encoded) {
+  final out = <int>[];
+  for (final token in encoded.split('.')) {
+    if (token.isEmpty) continue;
+    if (!token.contains('-')) {
+      final value = int.tryParse(token, radix: 36);
+      if (value == null || value < 0 || value > 254) return const [];
+      out.add(value);
+      continue;
+    }
+    final parts = token.split('-');
+    if (parts.length != 2) return const [];
+    final start = int.tryParse(parts[0], radix: 36);
+    final end = int.tryParse(parts[1], radix: 36);
+    if (start == null || end == null || start < 0 || end > 254 || start > end) {
+      return const [];
+    }
+    for (var i = start; i <= end; i++) {
+      out.add(i);
+    }
+  }
+  return out;
 }
 
 /// Fragment the compressed image bytes into [ImagePacket] list.

lib/utils/voice_message_parser.dart

@@ -181,11 +181,11 @@ class VoicePacket {
 /// Lightweight public/direct message envelope advertising voice availability.
 ///
 /// Text format:
-///   VE1:{sid}:{mode}:{total}:{durMs}:{senderKey6}:{ts}:{ver}
+///   VE2:{sid}:{mode}:{total}:{durS}:{senderKey6}:{ts}
 /// Example:
-///   VE1:00112233:1:4:3200:aabbccddeeff:1234567890:1
+///   VE2:00112233:1:4:4:aabbccddeeff:kf12oi
 class VoiceEnvelope {
-  static const String _prefix = 'VE1:';
+  static const String _prefix = 'VE2:';
 
   final String sessionId;
   final VoicePacketMode mode;
@@ -202,7 +202,7 @@ class VoiceEnvelope {
     required this.durationMs,
     required this.senderKey6,
     required this.timestampSec,
-    this.version = 1,
+    this.version = 2,
   });
 
   static bool isVoiceEnvelopeText(String text) => text.startsWith(_prefix);
@@ -210,43 +210,41 @@ class VoiceEnvelope {
   static VoiceEnvelope? tryParseText(String text) {
     if (!isVoiceEnvelopeText(text)) return null;
     final body = text.substring(_prefix.length);
-    return _tryParseCompact(body);
+    return _tryParse(body);
   }
 
-  static VoiceEnvelope? _tryParseCompact(String body) {
+  static VoiceEnvelope? _tryParse(String body) {
     final parts = body.split(':');
-    if (parts.length != 7) return null;
+    if (parts.length != 6) return null;
     try {
-      final sid = parts[0];
+      final sid = _decodeSessionId(parts[0]);
-      final mode = int.tryParse(parts[1]);
+      final mode = _parseInt(parts[1], base36: true);
-      final total = int.tryParse(parts[2]);
+      final total = _parseInt(parts[2], base36: true);
-      final durMs = int.tryParse(parts[3]);
+      final durS = _parseInt(parts[3], base36: true);
       final senderKey6 = parts[4];
-      final ts = int.tryParse(parts[5]);
+      final ts = _parseInt(parts[5], base36: true);
-      final ver = int.tryParse(parts[6]);
 
-      if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sid)) {
+      if (sid == null) {
         return null;
       }
       if (mode == null || mode < 0 || mode >= VoicePacketMode.values.length) {
         return null;
       }
       if (total == null || total < 1 || total > 255) return null;
-      if (durMs == null || durMs < 0 || durMs > 10 * 60 * 1000) return null;
+      if (durS == null || durS < 0 || durS > 10 * 60) return null;
       if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(senderKey6)) {
         return null;
       }
       if (ts == null || ts <= 0) return null;
-      if (ver == null || ver != 1) return null;
 
       return VoiceEnvelope(
-        sessionId: sid.toLowerCase(),
+        sessionId: sid,
         mode: VoicePacketMode.fromId(mode),
         total: total,
-        durationMs: durMs,
+        durationMs: durS * 1000,
         senderKey6: senderKey6.toLowerCase(),
         timestampSec: ts,
-        version: ver,
+        version: 2,
       );
     } catch (_) {
       return null;
@@ -254,7 +252,8 @@ class VoiceEnvelope {
   }
 
   String encodeText() {
-    return '$_prefix${sessionId.toLowerCase()}:${mode.id}:$total:$durationMs:${senderKey6.toLowerCase()}:$timestampSec:$version';
+    final durationSec = (durationMs / 1000).ceil().clamp(0, 10 * 60);
+    return '$_prefix${_encodeSessionId(sessionId)}:${_toBase36(mode.id)}:${_toBase36(total)}:${_toBase36(durationSec)}:${senderKey6.toLowerCase()}:${_toBase36(timestampSec)}';
   }
 }
 
@@ -415,11 +414,12 @@ int _resolveBandwidthHz(int? rawBw) {
 /// Direct control-plane request to fetch voice packets for a session.
 ///
 /// Text format:
-///   VR1:{sid}:{want}:{requesterKey6}:{ts}:{ver}
+///   VR2:{sid}:{want}:{requesterKey6}:{ts}
 /// Example:
-///   VR1:00112233:a:aabbccddeeff:1234567890:1
+///   VR2:00112233:a:aabbccddeeff:kf12oi
 class VoiceFetchRequest {
-  static const String _prefix = 'VR1:';
+  static const String _prefix = 'VR2:';
+  static const int _binaryMagic = 0x72; // 'r'
 
   final String sessionId;
   final String want;
@@ -434,42 +434,82 @@ class VoiceFetchRequest {
     this.missingIndices = const [],
     required this.requesterKey6,
     required this.timestampSec,
-    this.version = 1,
+    this.version = 2,
   });
 
-  static bool isVoiceFetchRequestText(String text) => text.startsWith(_prefix);
+  static bool isVoiceFetchRequestText(String text) =>
+      text.startsWith(_prefix);
+  static bool isVoiceFetchRequestBinary(Uint8List payload) =>
+      payload.isNotEmpty && payload[0] == _binaryMagic;
 
   static VoiceFetchRequest? tryParseText(String text) {
     if (!isVoiceFetchRequestText(text)) return null;
     final body = text.substring(_prefix.length);
-    return _tryParseCompact(body);
+    return _tryParse(body);
   }
 
-  static VoiceFetchRequest? _tryParseCompact(String body) {
+  static VoiceFetchRequest? tryParseBinary(Uint8List payload) {
-    final parts = body.split(':');
+    if (!isVoiceFetchRequestBinary(payload)) return null;
-    if (parts.length != 5) return null;
+    if (payload.length < 17) return null; // magic+sid+flags+key6+ts+count
     try {
-      final sid = parts[0];
+      final sidBytes = payload.sublist(1, 5);
+      final sid = sidBytes
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final flags = payload[5];
+      final requesterKey6 = payload
+          .sublist(6, 12)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final ts =
+          (payload[12] << 24) |
+          (payload[13] << 16) |
+          (payload[14] << 8) |
+          payload[15];
+      final missingCount = payload[16];
+      if (payload.length != 17 + missingCount) return null;
+      final wantMissing = (flags & 0x01) == 0x01;
+      final missing = <int>[];
+      for (var i = 0; i < missingCount; i++) {
+        missing.add(payload[17 + i]);
+      }
+      return VoiceFetchRequest(
+        sessionId: sid,
+        want: wantMissing ? 'missing' : 'all',
+        missingIndices: missing,
+        requesterKey6: requesterKey6,
+        timestampSec: ts,
+        version: 2,
+      );
+    } catch (_) {
+      return null;
+    }
+  }
+
+  static VoiceFetchRequest? _tryParse(String body) {
+    final parts = body.split(':');
+    if (parts.length != 4) return null;
+    try {
+      final sid = _decodeSessionId(parts[0]);
       final wantToken = parts[1];
       final requesterKey6 = parts[2];
-      final ts = int.tryParse(parts[3]);
+      final ts = _parseInt(parts[3], base36: true);
-      final ver = int.tryParse(parts[4]);
       final normalizedWant = wantToken == 'a'
           ? 'all'
-          : (wantToken.startsWith('m-') ? 'missing' : wantToken);
+          : ((wantToken.startsWith('m'))
+                ? 'missing'
+                : wantToken);
 
-      if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sid)) {
+      if (sid == null) {
         return null;
       }
       final missingIndices = <int>[];
       if (normalizedWant == 'missing') {
-        final encoded = wantToken.substring(2);
+        final encoded = wantToken.substring(1);
         if (encoded.isEmpty) return null;
-        for (final raw in encoded.split(',')) {
+        missingIndices.addAll(_decodeMissingIndicesCompact(encoded));
-          final idx = int.tryParse(raw);
-          if (idx == null || idx < 0 || idx > 254) return null;
-          missingIndices.add(idx);
-        }
         if (missingIndices.isEmpty) return null;
       } else if (normalizedWant != 'all') {
         return null;
@@ -478,15 +518,14 @@ class VoiceFetchRequest {
         return null;
       }
       if (ts == null || ts <= 0) return null;
-      if (ver == null || ver != 1) return null;
 
       return VoiceFetchRequest(
-        sessionId: sid.toLowerCase(),
+        sessionId: sid,
         want: normalizedWant,
         missingIndices: missingIndices,
         requesterKey6: requesterKey6.toLowerCase(),
         timestampSec: ts,
-        version: ver,
+        version: 2,
       );
     } catch (_) {
       return null;
@@ -495,10 +534,168 @@ class VoiceFetchRequest {
 
   String encodeText() {
     final wantToken = want == 'missing' && missingIndices.isNotEmpty
-        ? 'm-${missingIndices.join(',')}'
+        ? 'm${_encodeMissingIndicesCompact(missingIndices)}'
         : (want == 'all' ? 'a' : want);
-    return '$_prefix${sessionId.toLowerCase()}:$wantToken:${requesterKey6.toLowerCase()}:$timestampSec:$version';
+    return '$_prefix${_encodeSessionId(sessionId)}:$wantToken:${requesterKey6.toLowerCase()}:${_toBase36(timestampSec)}';
   }
+
+  Uint8List encodeBinary() {
+    if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionId)) {
+      throw ArgumentError.value(sessionId, 'sessionId', 'Expected 8 hex chars');
+    }
+    if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(requesterKey6)) {
+      throw ArgumentError.value(
+        requesterKey6,
+        'requesterKey6',
+        'Expected 12 hex chars',
+      );
+    }
+    final useMissing = want == 'missing' && missingIndices.isNotEmpty;
+    final missing = useMissing
+        ? missingIndices.where((v) => v >= 0 && v <= 254).toList()
+        : <int>[];
+
+    final out = Uint8List(17 + missing.length);
+    out[0] = _binaryMagic;
+    for (var i = 0; i < 4; i++) {
+      out[1 + i] = int.parse(sessionId.substring(i * 2, i * 2 + 2), radix: 16);
+    }
+    out[5] = useMissing ? 0x01 : 0x00;
+    for (var i = 0; i < 6; i++) {
+      out[6 + i] = int.parse(
+        requesterKey6.substring(i * 2, i * 2 + 2),
+        radix: 16,
+      );
+    }
+    out[12] = (timestampSec >> 24) & 0xFF;
+    out[13] = (timestampSec >> 16) & 0xFF;
+    out[14] = (timestampSec >> 8) & 0xFF;
+    out[15] = timestampSec & 0xFF;
+    out[16] = missing.length;
+    for (var i = 0; i < missing.length; i++) {
+      out[17 + i] = missing[i];
+    }
+    return out;
+  }
+}
+
+/// Per-fragment ACK for raw voice payload packets.
+///
+/// Binary format:
+///   [0x76 'v'][sessionId:4B][index:1B]
+class VoiceFragmentAck {
+  static const int _binaryMagic = 0x76; // 'v'
+
+  final String sessionId; // 8 hex chars
+  final int index; // 0..254
+
+  const VoiceFragmentAck({required this.sessionId, required this.index});
+
+  static bool isVoiceFragmentAckBinary(Uint8List payload) =>
+      payload.length == 6 && payload[0] == _binaryMagic;
+
+  static VoiceFragmentAck? tryParseBinary(Uint8List payload) {
+    if (!isVoiceFragmentAckBinary(payload)) return null;
+    try {
+      final sid = payload
+          .sublist(1, 5)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      final idx = payload[5];
+      return VoiceFragmentAck(sessionId: sid, index: idx);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  Uint8List encodeBinary() {
+    if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionId)) {
+      throw ArgumentError.value(sessionId, 'sessionId', 'Expected 8 hex chars');
+    }
+    if (index < 0 || index > 254) {
+      throw ArgumentError.value(index, 'index', 'Expected 0..254');
+    }
+    final out = Uint8List(6);
+    out[0] = _binaryMagic;
+    for (var i = 0; i < 4; i++) {
+      out[1 + i] = int.parse(sessionId.substring(i * 2, i * 2 + 2), radix: 16);
+    }
+    out[5] = index;
+    return out;
+  }
+}
+
+int? _parseInt(String token, {required bool base36}) =>
+    int.tryParse(token, radix: base36 ? 36 : 10);
+
+String _toBase36(int value) => value.toRadixString(36);
+
+String _encodeSessionId(String sessionIdHex) {
+  if (!RegExp(r'^[0-9a-fA-F]{8}$').hasMatch(sessionIdHex)) {
+    throw ArgumentError.value(sessionIdHex, 'sessionIdHex', 'Expected 8 hex chars');
+  }
+  final value = int.parse(sessionIdHex, radix: 16);
+  return value.toRadixString(36);
+}
+
+String? _decodeSessionId(String token) {
+  if (!RegExp(r'^[0-9a-z]{1,7}$').hasMatch(token)) return null;
+  final value = int.tryParse(token, radix: 36);
+  if (value == null || value < 0 || value > 0xFFFFFFFF) return null;
+  return value.toRadixString(16).padLeft(8, '0');
+}
+
+String _encodeMissingIndicesCompact(List<int> indices) {
+  final sorted = indices
+      .where((v) => v >= 0 && v <= 254)
+      .toSet()
+      .toList()
+    ..sort();
+  if (sorted.isEmpty) return '';
+  final chunks = <String>[];
+  var start = sorted.first;
+  var prev = sorted.first;
+  for (var i = 1; i < sorted.length; i++) {
+    final curr = sorted[i];
+    if (curr == prev + 1) {
+      prev = curr;
+      continue;
+    }
+    chunks.add(
+      start == prev ? _toBase36(start) : '${_toBase36(start)}-${_toBase36(prev)}',
+    );
+    start = curr;
+    prev = curr;
+  }
+  chunks.add(
+    start == prev ? _toBase36(start) : '${_toBase36(start)}-${_toBase36(prev)}',
+  );
+  return chunks.join('.');
+}
+
+List<int> _decodeMissingIndicesCompact(String encoded) {
+  final out = <int>[];
+  for (final token in encoded.split('.')) {
+    if (token.isEmpty) continue;
+    if (!token.contains('-')) {
+      final value = int.tryParse(token, radix: 36);
+      if (value == null || value < 0 || value > 254) return const [];
+      out.add(value);
+      continue;
+    }
+    final parts = token.split('-');
+    if (parts.length != 2) return const [];
+    final start = int.tryParse(parts[0], radix: 36);
+    final end = int.tryParse(parts[1], radix: 36);
+    if (start == null || end == null || start < 0 || end > 254 || start > end) {
+      return const [];
+    }
+    for (var i = start; i <= end; i++) {
+      out.add(i);
+    }
+  }
+  return out;
 }
 
 /// Builds a compact visual waveform from real voice packet bytes.

lib/widgets/messages/image_message_bubble.dart

@@ -13,8 +13,8 @@ import 'transfer_timeout.dart';
 
 /// A message bubble that shows a received or sent image.
 ///
-/// On first render the image is not yet fetched (only the IE1 envelope is
+/// On first render the image is not yet fetched (only the IE2 envelope is
-/// known).  The user taps the thumbnail placeholder → IR1 fetch request is
+/// known).  The user taps the thumbnail placeholder → IR2 fetch request is
 /// sent → binary fragments stream in → bubble rebuilds with the full image.
 class ImageMessageBubble extends StatefulWidget {
   final Message message;
@@ -279,18 +279,23 @@ class _ImageMessageBubbleState extends State<ImageMessageBubble> {
       _errorText = null;
     });
 
-    final sent = await conn.sendTextMessage(
+    final payload = request.encodeBinary();
-      contactPublicKey: sender.publicKey,
+    try {
-      text: request.encode(),
+      await conn.sendRawVoicePacket(
-      contact: sender,
+        contactPath: sender.outPath,
+        contactPathLen: sender.outPathLen,
+        payload: payload,
       );
-    if (!sent && mounted) {
+    } catch (_) {
+      if (mounted) {
         setState(() {
           _isRequesting = false;
           _errorText = 'Image unavailable right now';
         });
+      }
       return;
     }
+    if (!mounted) return;
 
     // Timeout = 2× estimated LoRa airtime (min 30s).
     final txEstimate = estimateImageTransmitDuration(

lib/widgets/messages/message_bubble.dart

@@ -1682,6 +1682,13 @@ class _MessageBubbleState extends State<MessageBubble> {
     }
 
     final message = widget.message;
+    final ticTacToeEvent = message.isContactMessage
+        ? TicTacToeMessageParser.tryParse(message.text)
+        : null;
+    if (ticTacToeEvent?.type == TicTacToeEventType.move) {
+      // Hide move control packets from chat; the game bubble updates itself.
+      return const SizedBox.shrink();
+    }
     final isSarMarker = message.isSarMarker;
     final isDarkMode = Theme.of(context).brightness == Brightness.dark;
 
@@ -2183,8 +2190,7 @@ class _MessageBubbleState extends State<MessageBubble> {
                 !widget.isCompact)
               ImageMessageBubble(message: message, isSentByMe: isOwnMessage)
             // Tic-Tac-Toe control message content
-            else if (message.isContactMessage &&
+            else if (ticTacToeEvent?.type == TicTacToeEventType.start &&
-                TicTacToeMessageParser.isTicTacToe(message.text) &&
                 !widget.isCompact)
               TicTacToeMessageBubble(message: message, isSentByMe: isOwnMessage)
             // Regular message content

lib/widgets/messages/voice_message_bubble.dart

@@ -259,7 +259,7 @@ class _VoiceMessageBubbleState extends State<VoiceMessageBubble> {
       sessionId: sessionId,
       requesterKey6: requesterKey6,
       timestampSec: DateTime.now().millisecondsSinceEpoch ~/ 1000,
-      version: 1,
+      version: 2,
     );
 
     setState(() {
@@ -268,12 +268,13 @@ class _VoiceMessageBubbleState extends State<VoiceMessageBubble> {
       _errorText = null;
     });
 
-    final sent = await connectionProvider.sendTextMessage(
+    try {
-      contactPublicKey: sender.publicKey,
+      await connectionProvider.sendRawVoicePacket(
-      text: request.encodeText(),
+        contactPath: sender.outPath,
-      contact: sender,
+        contactPathLen: sender.outPathLen,
+        payload: request.encodeBinary(),
       );
-    if (!sent) {
+    } catch (_) {
       _setUnavailable();
       return;
     }

test/providers/messages_provider_voice_test.dart

@@ -8,7 +8,7 @@ void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('MessagesProvider voice detection', () {
-    test('marks VE1 envelope messages as voice', () {
+    test('marks VE2 envelope messages as voice', () {
       final provider = MessagesProvider();
       final envelope = VoiceEnvelope(
         sessionId: 'deafbead',

test/utils/image_message_parser_test.dart

@@ -0,0 +1,116 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_sar_app/utils/image_message_parser.dart';
+
+void main() {
+  group('ImageEnvelope', () {
+    test('encodes and parses IE2 with compressed session id', () {
+      final env = ImageEnvelope(
+        sessionId: '0000000a',
+        format: ImageFormat.avif,
+        total: 14,
+        width: 256,
+        height: 171,
+        sizeBytes: 2100,
+        senderKey6: 'aabbccddeeff',
+        timestampSec: 1700000000,
+      );
+
+      final text = env.encode();
+      expect(text.startsWith('IE2:'), isTrue);
+      expect(text.split(':')[1], equals('a'));
+
+      final parsed = ImageEnvelope.tryParse(text);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('0000000a'));
+      expect(parsed.format, equals(ImageFormat.avif));
+      expect(parsed.total, equals(14));
+      expect(parsed.width, equals(256));
+      expect(parsed.height, equals(171));
+      expect(parsed.sizeBytes, equals(2100));
+      expect(parsed.senderKey6, equals('aabbccddeeff'));
+      expect(parsed.version, equals(2));
+    });
+
+    test('rejects IE1 legacy prefix', () {
+      const legacy = 'IE1:deadbeef:0:7:128:128:1050:aabbccddeeff:1700000000:1';
+      expect(ImageEnvelope.tryParse(legacy), isNull);
+    });
+  });
+
+  group('ImageFetchRequest', () {
+    test('encodes and parses IR2 with compressed sid', () {
+      final req = ImageFetchRequest(
+        sessionId: '0000000a',
+        requesterKey6: 'ffeeddccbbaa',
+        timestampSec: 1700000001,
+      );
+
+      final text = req.encode();
+      expect(text.startsWith('IR2:'), isTrue);
+      expect(text.split(':')[1], equals('a'));
+
+      final parsed = ImageFetchRequest.tryParse(text);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('0000000a'));
+      expect(parsed.want, equals('all'));
+      expect(parsed.requesterKey6, equals('ffeeddccbbaa'));
+      expect(parsed.version, equals(2));
+    });
+
+    test('encodes and parses compact missing index ranges', () {
+      final req = ImageFetchRequest(
+        sessionId: '0000000a',
+        want: 'missing',
+        missingIndices: const [0, 1, 2, 5, 6, 8],
+        requesterKey6: 'ffeeddccbbaa',
+        timestampSec: 1700000001,
+      );
+
+      final text = req.encode();
+      expect(text, contains(':m0-2.5-6.8:'));
+
+      final parsed = ImageFetchRequest.tryParse(text);
+      expect(parsed, isNotNull);
+      expect(parsed!.want, equals('missing'));
+      expect(parsed.missingIndices, equals([0, 1, 2, 5, 6, 8]));
+    });
+
+    test('rejects IR1 legacy prefix', () {
+      const legacy = 'IR1:00112233:a:ffeeddccbbaa:1700000001:1';
+      expect(ImageFetchRequest.tryParse(legacy), isNull);
+    });
+
+    test('encodes and parses binary fetch request', () {
+      final req = ImageFetchRequest(
+        sessionId: '01020304',
+        want: 'missing',
+        missingIndices: const [0, 2, 5],
+        requesterKey6: 'ffeeddccbbaa',
+        timestampSec: 1700000001,
+      );
+
+      final payload = req.encodeBinary();
+      expect(ImageFetchRequest.isRequestBinary(payload), isTrue);
+
+      final parsed = ImageFetchRequest.tryParseBinary(payload);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('01020304'));
+      expect(parsed.want, equals('missing'));
+      expect(parsed.missingIndices, equals([0, 2, 5]));
+      expect(parsed.requesterKey6, equals('ffeeddccbbaa'));
+      expect(parsed.version, equals(2));
+    });
+  });
+
+  group('ImageFragmentAck', () {
+    test('encodes and parses binary ack', () {
+      final ack = ImageFragmentAck(sessionId: '01020304', index: 9);
+      final payload = ack.encodeBinary();
+      expect(ImageFragmentAck.isImageFragmentAckBinary(payload), isTrue);
+      final parsed = ImageFragmentAck.tryParseBinary(payload);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('01020304'));
+      expect(parsed.index, equals(9));
+    });
+  });
+}

test/utils/voice_message_parser_test.dart

@@ -6,74 +6,122 @@ void main() {
   group('VoiceEnvelope', () {
     test('encodes and parses valid envelope', () {
       final env = VoiceEnvelope(
-        sessionId: 'deadbeef',
+        sessionId: '0000000a',
         mode: VoicePacketMode.mode1200,
         total: 4,
-        durationMs: 3200,
+        durationMs: 3000,
         senderKey6: 'aabbccddeeff',
         timestampSec: 1700000000,
       );
 
       final text = env.encodeText();
       expect(VoiceEnvelope.isVoiceEnvelopeText(text), isTrue);
+      expect(text.startsWith('VE2:'), isTrue);
+      expect(text.split(':')[1], equals('a'));
 
       final parsed = VoiceEnvelope.tryParseText(text);
       expect(parsed, isNotNull);
-      expect(parsed!.sessionId, equals('deadbeef'));
+      expect(parsed!.sessionId, equals('0000000a'));
       expect(parsed.mode, equals(VoicePacketMode.mode1200));
       expect(parsed.total, equals(4));
-      expect(parsed.durationMs, equals(3200));
+      expect(parsed.durationMs, equals(3000));
       expect(parsed.senderKey6, equals('aabbccddeeff'));
-      expect(parsed.version, equals(1));
+      expect(parsed.version, equals(2));
     });
 
     test('rejects invalid envelope payload', () {
-      final text = 'VE1:nothex:1:2:1000:aabbccddeeff:1700000000:1';
+      final text = 'VE2:bad_sid:1:2:1000:aabbccddeeff:s44we8';
       expect(VoiceEnvelope.tryParseText(text), isNull);
     });
+
+    test('rejects legacy v1 envelope prefix', () {
+      const legacy = 'VE1:deadbeef:1:4:3200:aabbccddeeff:1700000000:1';
+      expect(VoiceEnvelope.tryParseText(legacy), isNull);
+    });
   });
 
   group('VoiceFetchRequest', () {
     test('encodes and parses valid request', () {
       final req = VoiceFetchRequest(
-        sessionId: '00112233',
+        sessionId: '0000000a',
         requesterKey6: 'ffeeddccbbaa',
         timestampSec: 1700000001,
       );
       final text = req.encodeText();
       expect(VoiceFetchRequest.isVoiceFetchRequestText(text), isTrue);
+      expect(text.startsWith('VR2:'), isTrue);
+      expect(text.split(':')[1], equals('a'));
 
       final parsed = VoiceFetchRequest.tryParseText(text);
       expect(parsed, isNotNull);
-      expect(parsed!.sessionId, equals('00112233'));
+      expect(parsed!.sessionId, equals('0000000a'));
       expect(parsed.want, equals('all'));
       expect(parsed.requesterKey6, equals('ffeeddccbbaa'));
-      expect(parsed.version, equals(1));
+      expect(parsed.version, equals(2));
     });
 
     test('rejects invalid request payload', () {
       expect(
         VoiceFetchRequest.tryParseText(
-          'VR1:00112233:chunk:ffeeddccbbaa:1700000001:1',
+          'VR2:a:chunk:ffeeddccbbaa:s44we9',
         ),
         isNull,
       );
     });
 
+    test('rejects legacy v1 request prefix', () {
+      const legacy = 'VR1:00112233:a:ffeeddccbbaa:1700000001:1';
+      expect(VoiceFetchRequest.tryParseText(legacy), isNull);
+    });
+
     test('encodes and parses missing-packet request', () {
       final req = VoiceFetchRequest(
-        sessionId: '00112233',
+        sessionId: '0000000a',
         want: 'missing',
-        missingIndices: const [0, 3, 7],
+        missingIndices: const [0, 1, 2, 3, 7],
         requesterKey6: 'ffeeddccbbaa',
         timestampSec: 1700000001,
       );
       final text = req.encodeText();
+      expect(text, contains(':m0-3.7:'));
 
       final parsed = VoiceFetchRequest.tryParseText(text);
       expect(parsed, isNotNull);
       expect(parsed!.want, equals('missing'));
-      expect(parsed.missingIndices, equals([0, 3, 7]));
+      expect(parsed.missingIndices, equals([0, 1, 2, 3, 7]));
+    });
+
+    test('encodes and parses binary fetch request', () {
+      final req = VoiceFetchRequest(
+        sessionId: '01020304',
+        want: 'missing',
+        missingIndices: const [1, 4],
+        requesterKey6: 'ffeeddccbbaa',
+        timestampSec: 1700000001,
+      );
+
+      final payload = req.encodeBinary();
+      expect(VoiceFetchRequest.isVoiceFetchRequestBinary(payload), isTrue);
+
+      final parsed = VoiceFetchRequest.tryParseBinary(payload);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('01020304'));
+      expect(parsed.want, equals('missing'));
+      expect(parsed.missingIndices, equals([1, 4]));
+      expect(parsed.requesterKey6, equals('ffeeddccbbaa'));
+      expect(parsed.version, equals(2));
+    });
+  });
+
+  group('VoiceFragmentAck', () {
+    test('encodes and parses binary ack', () {
+      final ack = VoiceFragmentAck(sessionId: '01020304', index: 7);
+      final payload = ack.encodeBinary();
+      expect(VoiceFragmentAck.isVoiceFragmentAckBinary(payload), isTrue);
+      final parsed = VoiceFragmentAck.tryParseBinary(payload);
+      expect(parsed, isNotNull);
+      expect(parsed!.sessionId, equals('01020304'));
+      expect(parsed.index, equals(7));
     });
   });