Use libsignal-net for multi-recipient send.

app/src/main/java/org/thoughtcrime/securesms/jobs/GroupCallUpdateSendJob.java

@@ -147,6 +147,11 @@ public class GroupCallUpdateSendJob extends BaseJob {
            e instanceof RetryLaterException;
   }
 
+  @Override
+  public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
+  }
+
   @Override
   public void onFailure() {
     if (recipients.size() < initialRecipientCount) {

app/src/main/java/org/thoughtcrime/securesms/jobs/ProfileKeySendJob.java

@@ -165,6 +165,11 @@ public class ProfileKeySendJob extends BaseJob {
            e instanceof RetryLaterException;
   }
 
+  @Override
+  public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
+  }
+
   @Override
   public @Nullable byte[] serialize() {
     return new JsonJobData.Builder()

app/src/main/java/org/thoughtcrime/securesms/jobs/PushGroupSilentUpdateSendJob.java

@@ -9,14 +9,17 @@ import androidx.annotation.WorkerThread;
 import com.annimon.stream.Collectors;
 import com.annimon.stream.Stream;
 
+import org.signal.core.models.ServiceId;
+import org.signal.core.models.ServiceId.ACI;
+import org.signal.core.util.Base64;
 import org.signal.core.util.logging.Log;
 import org.signal.storageservice.storage.protos.groups.local.DecryptedGroup;
 import org.thoughtcrime.securesms.database.RecipientTable;
 import org.thoughtcrime.securesms.database.SignalDatabase;
 import org.thoughtcrime.securesms.groups.GroupId;
 import org.thoughtcrime.securesms.jobmanager.Job;
-import org.thoughtcrime.securesms.jobmanager.impl.SealedSenderConstraint;
 import org.thoughtcrime.securesms.jobmanager.JsonJobData;
+import org.thoughtcrime.securesms.jobmanager.impl.SealedSenderConstraint;
 import org.thoughtcrime.securesms.keyvalue.SignalStore;
 import org.thoughtcrime.securesms.messages.GroupSendUtil;
 import org.thoughtcrime.securesms.mms.MessageGroupContext;
@@ -25,7 +28,6 @@ import org.thoughtcrime.securesms.net.NotPushRegisteredException;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientId;
 import org.thoughtcrime.securesms.transport.RetryLaterException;
-import org.signal.core.util.Base64;
 import org.thoughtcrime.securesms.util.GroupUtil;
 import org.whispersystems.signalservice.api.crypto.ContentHint;
 import org.whispersystems.signalservice.api.crypto.UntrustedIdentityException;
@@ -33,8 +35,6 @@ import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil;
 import org.whispersystems.signalservice.api.messages.SendMessageResult;
 import org.whispersystems.signalservice.api.messages.SignalServiceDataMessage;
 import org.whispersystems.signalservice.api.messages.SignalServiceGroupV2;
-import org.signal.core.models.ServiceId;
-import org.signal.core.models.ServiceId.ACI;
 import org.whispersystems.signalservice.api.push.exceptions.ServerRejectedException;
 import org.whispersystems.signalservice.internal.push.GroupContextV2;
 
@@ -168,6 +168,11 @@ public final class PushGroupSilentUpdateSendJob extends BaseJob {
            e instanceof RetryLaterException;
   }
 
+  @Override
+  public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
+  }
+
   @Override
   public void onFailure() {
     Log.w(TAG, "Failed to send remote delete to all recipients! (" + (initialRecipientCount - recipients.size() + "/" + initialRecipientCount + ")") );

app/src/main/java/org/thoughtcrime/securesms/jobs/PushSendJob.java

@@ -72,6 +72,7 @@ import org.signal.core.models.ServiceId.ACI;
 import org.whispersystems.signalservice.api.push.exceptions.NonSuccessfulResponseCodeException;
 import org.whispersystems.signalservice.api.push.exceptions.ProofRequiredException;
 import org.whispersystems.signalservice.api.push.exceptions.RateLimitException;
+import org.whispersystems.signalservice.api.push.exceptions.RetryNetworkException;
 import org.whispersystems.signalservice.api.push.exceptions.ServerRejectedException;
 import org.whispersystems.signalservice.internal.push.BodyRange;
 
@@ -160,29 +161,7 @@ public abstract class PushSendJob extends SendJob {
 
   @Override
   public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
-    if (exception instanceof ProofRequiredException) {
-      long backoff = ((ProofRequiredException) exception).getRetryAfterSeconds();
-      warn(TAG, "[Proof Required] Retry-After is " + backoff + " seconds.");
-      if (backoff >= 0) {
-        return TimeUnit.SECONDS.toMillis(backoff);
-      }
-    } else if (exception instanceof RateLimitException) {
-      long backoff = ((RateLimitException) exception).getRetryAfterMilliseconds().orElse(-1L);
-      if (backoff >= 0) {
-        return backoff;
-      }
-    } else if (exception instanceof NonSuccessfulResponseCodeException) {
-      if (((NonSuccessfulResponseCodeException) exception).is5xx()) {
-        return BackoffUtil.exponentialBackoff(pastAttemptCount, RemoteConfig.getServerErrorMaxBackoff());
-      }
-    } else if (exception instanceof RetryLaterException) {
-      long backoff = ((RetryLaterException) exception).getBackoff();
-      if (backoff >= 0) {
-        return backoff;
-      }
-    }
-
-    return super.getNextRunAttemptBackoff(pastAttemptCount, exception);
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
   }
 
   protected Optional<byte[]> getProfileKey(@NonNull Recipient recipient) {

app/src/main/java/org/thoughtcrime/securesms/jobs/ReactionSendJob.java

@@ -15,8 +15,8 @@ import org.thoughtcrime.securesms.database.model.MessageRecord;
 import org.thoughtcrime.securesms.database.model.ReactionRecord;
 import org.thoughtcrime.securesms.dependencies.AppDependencies;
 import org.thoughtcrime.securesms.groups.GroupId;
-import org.thoughtcrime.securesms.jobmanager.JsonJobData;
 import org.thoughtcrime.securesms.jobmanager.Job;
+import org.thoughtcrime.securesms.jobmanager.JsonJobData;
 import org.thoughtcrime.securesms.jobmanager.impl.NetworkConstraint;
 import org.thoughtcrime.securesms.jobmanager.impl.SealedSenderConstraint;
 import org.thoughtcrime.securesms.keyvalue.SignalStore;
@@ -193,6 +193,11 @@ public class ReactionSendJob extends BaseJob {
            e instanceof RetryLaterException;
   }
 
+  @Override
+  public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
+  }
+
   @Override
   public void onFailure() {
     if (recipients.size() < initialRecipientCount) {

app/src/main/java/org/thoughtcrime/securesms/jobs/RemoteDeleteSendJob.java

@@ -7,6 +7,7 @@ import androidx.annotation.WorkerThread;
 import com.annimon.stream.Stream;
 
 import org.signal.core.util.SetUtil;
+import org.signal.core.util.Util;
 import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.database.MessageTable;
 import org.thoughtcrime.securesms.database.NoSuchMessageException;
@@ -17,9 +18,9 @@ import org.thoughtcrime.securesms.database.model.MessageRecord;
 import org.thoughtcrime.securesms.database.model.MmsMessageRecord;
 import org.thoughtcrime.securesms.dependencies.AppDependencies;
 import org.thoughtcrime.securesms.groups.GroupId;
-import org.thoughtcrime.securesms.jobmanager.JsonJobData;
 import org.thoughtcrime.securesms.jobmanager.Job;
 import org.thoughtcrime.securesms.jobmanager.JobManager;
+import org.thoughtcrime.securesms.jobmanager.JsonJobData;
 import org.thoughtcrime.securesms.jobmanager.impl.SealedSenderConstraint;
 import org.thoughtcrime.securesms.messages.GroupSendUtil;
 import org.thoughtcrime.securesms.net.NotPushRegisteredException;
@@ -28,7 +29,6 @@ import org.thoughtcrime.securesms.recipients.RecipientId;
 import org.thoughtcrime.securesms.recipients.RecipientUtil;
 import org.thoughtcrime.securesms.transport.RetryLaterException;
 import org.thoughtcrime.securesms.util.GroupUtil;
-import org.signal.core.util.Util;
 import org.whispersystems.signalservice.api.crypto.ContentHint;
 import org.whispersystems.signalservice.api.crypto.UntrustedIdentityException;
 import org.whispersystems.signalservice.api.messages.SendMessageResult;
@@ -198,6 +198,11 @@ public class RemoteDeleteSendJob extends BaseJob {
            e instanceof RetryLaterException;
   }
 
+  @Override
+  public long getNextRunAttemptBackoff(int pastAttemptCount, @NonNull Exception exception) {
+    return SendJobUtil.getBackoffMillisFromException(this, TAG, pastAttemptCount, exception, () -> super.getNextRunAttemptBackoff(pastAttemptCount, exception));
+  }
+
   @Override
   public void onFailure() {
     Log.w(TAG, "Failed to send remote delete to all recipients! (" + (initialRecipientCount - recipients.size() + "/" + initialRecipientCount + ")") );

app/src/main/java/org/thoughtcrime/securesms/jobs/SendJobExtensions.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+@file:JvmName("SendJobUtil")
+
+package org.thoughtcrime.securesms.jobs
+
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.jobmanager.Job
+import org.thoughtcrime.securesms.jobmanager.JobLogger
+import org.thoughtcrime.securesms.jobmanager.impl.BackoffUtil
+import org.thoughtcrime.securesms.transport.RetryLaterException
+import org.thoughtcrime.securesms.util.RemoteConfig.serverErrorMaxBackoff
+import org.whispersystems.signalservice.api.push.exceptions.NonSuccessfulResponseCodeException
+import org.whispersystems.signalservice.api.push.exceptions.ProofRequiredException
+import org.whispersystems.signalservice.api.push.exceptions.RateLimitException
+import org.whispersystems.signalservice.api.push.exceptions.RetryNetworkException
+import java.util.concurrent.TimeUnit
+import org.signal.libsignal.net.RetryLaterException as LibSignalRetryLaterException
+
+fun Job.getBackoffMillisFromException(tag: String, pastAttemptCount: Int, exception: Exception, default: () -> Long): Long {
+  when (exception) {
+    is ProofRequiredException -> {
+      val backoff = exception.retryAfterSeconds
+      Log.w(tag, JobLogger.format(this, "[Proof Required] Retry-After is $backoff seconds."))
+      if (backoff >= 0) {
+        return TimeUnit.SECONDS.toMillis(backoff)
+      }
+    }
+
+    is RateLimitException -> {
+      val backoff = exception.retryAfterMilliseconds.orElse(-1L)
+      if (backoff >= 0) {
+        return backoff
+      }
+    }
+
+    is NonSuccessfulResponseCodeException -> {
+      if (exception.is5xx()) {
+        return BackoffUtil.exponentialBackoff(pastAttemptCount, serverErrorMaxBackoff)
+      }
+    }
+
+    is LibSignalRetryLaterException -> {
+      return exception.duration.toMillis()
+    }
+
+    is RetryNetworkException -> {
+      return exception.retryAfterMs
+    }
+
+    is RetryLaterException -> {
+      val backoff = exception.backoff
+      if (backoff >= 0) {
+        return backoff
+      }
+    }
+  }
+
+  return default()
+}

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/NetworkResultUtil.kt

@@ -13,13 +13,9 @@ import org.whispersystems.signalservice.api.push.exceptions.RateLimitException
 import org.whispersystems.signalservice.api.push.exceptions.ServerRejectedException
 import org.whispersystems.signalservice.api.push.exceptions.UnregisteredUserException
 import org.whispersystems.signalservice.api.websocket.WebSocketUnavailableException
-import org.whispersystems.signalservice.internal.push.SendGroupMessageResponse
 import org.whispersystems.signalservice.internal.push.SendMessageResponse
-import org.whispersystems.signalservice.internal.push.exceptions.GroupMismatchedDevicesException
-import org.whispersystems.signalservice.internal.push.exceptions.GroupStaleDevicesException
 import org.whispersystems.signalservice.internal.push.exceptions.InAppPaymentProcessorError
 import org.whispersystems.signalservice.internal.push.exceptions.InAppPaymentReceiptCredentialError
-import org.whispersystems.signalservice.internal.push.exceptions.InvalidUnidentifiedAccessHeaderException
 import org.whispersystems.signalservice.internal.push.exceptions.MismatchedDevicesException
 import org.whispersystems.signalservice.internal.push.exceptions.PaymentsRegionException
 import org.whispersystems.signalservice.internal.push.exceptions.StaleDevicesException
@@ -117,44 +113,6 @@ object NetworkResultUtil {
     }
   }
 
-  /**
-   * Convert [NetworkResult] into expected type exceptions for a multi-recipient message send.
-   */
-  @JvmStatic
-  @Throws(
-    InvalidUnidentifiedAccessHeaderException::class,
-    NotFoundException::class,
-    GroupMismatchedDevicesException::class,
-    GroupStaleDevicesException::class,
-    RateLimitException::class,
-    ServerRejectedException::class,
-    WebSocketUnavailableException::class,
-    IOException::class
-  )
-  fun toGroupMessageSendLegacy(result: NetworkResult<SendGroupMessageResponse>): SendGroupMessageResponse {
-    return when (result) {
-      is NetworkResult.Success -> result.result
-      is NetworkResult.ApplicationError -> {
-        throw when (val error = result.throwable) {
-          is IOException, is RuntimeException -> error
-          else -> RuntimeException(error)
-        }
-      }
-      is NetworkResult.NetworkError -> throw result.exception
-      is NetworkResult.StatusCodeError -> {
-        throw when (result.code) {
-          401 -> InvalidUnidentifiedAccessHeaderException()
-          404 -> NotFoundException("At least one unregistered user is message send.")
-          409 -> GroupMismatchedDevicesException(result.parseJsonBody())
-          410 -> GroupStaleDevicesException(result.parseJsonBody())
-          413, 429 -> throw RateLimitException(result.code, "Rate Limited", Optional.ofNullable(result.header("retry-after")?.toLongOrNull()?.seconds?.inWholeMilliseconds))
-          508 -> ServerRejectedException()
-          else -> result.exception
-        }
-      }
-    }
-  }
-
   @JvmStatic
   @Throws(IOException::class)
   fun <T> toPreKeysLegacy(result: NetworkResult<T>): T {

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java

@@ -11,6 +11,13 @@ import org.signal.core.util.Base64;
 import org.signal.core.util.ProtoUtil;
 import org.signal.core.util.UuidUtil;
 import org.signal.libsignal.metadata.certificate.SenderCertificate;
+import org.signal.libsignal.net.MismatchedDeviceException;
+import org.signal.libsignal.net.MultiRecipientMessageResponse;
+import org.signal.libsignal.net.MultiRecipientSendAuthorization;
+import org.signal.libsignal.net.MultiRecipientSendFailure;
+import org.signal.libsignal.net.RequestResult;
+import org.signal.libsignal.net.RequestUnauthorizedException;
+import org.signal.libsignal.net.RetryLaterException;
 import org.signal.libsignal.protocol.IdentityKey;
 import org.signal.libsignal.protocol.IdentityKeyPair;
 import org.signal.libsignal.protocol.InvalidKeyException;
@@ -39,6 +46,7 @@ import org.whispersystems.signalservice.api.crypto.UntrustedIdentityException;
 import org.whispersystems.signalservice.api.groupsv2.GroupSendEndorsements;
 import org.whispersystems.signalservice.api.keys.KeysApi;
 import org.whispersystems.signalservice.api.message.MessageApi;
+import org.whispersystems.signalservice.api.message.MessageApiKt;
 import org.whispersystems.signalservice.api.messages.SendMessageResult;
 import org.whispersystems.signalservice.api.messages.SignalServiceAttachment;
 import org.whispersystems.signalservice.api.messages.SignalServiceAttachmentPointer;
@@ -75,11 +83,12 @@ import org.whispersystems.signalservice.api.push.DistributionId;
 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
 import org.whispersystems.signalservice.api.push.exceptions.AuthorizationFailedException;
 import org.whispersystems.signalservice.api.push.exceptions.NonSuccessfulResponseCodeException;
-import org.whispersystems.signalservice.api.push.exceptions.NotFoundException;
 import org.whispersystems.signalservice.api.push.exceptions.ProofRequiredException;
 import org.whispersystems.signalservice.api.push.exceptions.PushNetworkException;
 import org.whispersystems.signalservice.api.push.exceptions.RateLimitException;
+import org.whispersystems.signalservice.api.push.exceptions.RetryNetworkException;
 import org.whispersystems.signalservice.api.push.exceptions.ServerRejectedException;
+import org.whispersystems.signalservice.api.push.exceptions.UnknownGroupSendException;
 import org.whispersystems.signalservice.api.push.exceptions.UnregisteredUserException;
 import org.whispersystems.signalservice.api.util.AttachmentPointerUtil;
 import org.whispersystems.signalservice.api.util.CredentialsProvider;
@@ -97,8 +106,6 @@ import org.whispersystems.signalservice.internal.push.Content;
 import org.whispersystems.signalservice.internal.push.DataMessage;
 import org.whispersystems.signalservice.internal.push.EditMessage;
 import org.whispersystems.signalservice.internal.push.GroupContextV2;
-import org.whispersystems.signalservice.internal.push.GroupMismatchedDevices;
-import org.whispersystems.signalservice.internal.push.GroupStaleDevices;
 import org.whispersystems.signalservice.internal.push.MismatchedDevices;
 import org.whispersystems.signalservice.internal.push.NullMessage;
 import org.whispersystems.signalservice.internal.push.OutgoingPushMessage;
@@ -109,7 +116,6 @@ import org.whispersystems.signalservice.internal.push.ProvisioningVersion;
 import org.whispersystems.signalservice.internal.push.PushAttachmentData;
 import org.whispersystems.signalservice.internal.push.PushServiceSocket;
 import org.whispersystems.signalservice.internal.push.ReceiptMessage;
-import org.whispersystems.signalservice.internal.push.SendGroupMessageResponse;
 import org.whispersystems.signalservice.internal.push.SendMessageResponse;
 import org.whispersystems.signalservice.internal.push.StaleDevices;
 import org.whispersystems.signalservice.internal.push.StoryMessage;
@@ -117,8 +123,6 @@ import org.whispersystems.signalservice.internal.push.SyncMessage;
 import org.whispersystems.signalservice.internal.push.TextAttachment;
 import org.whispersystems.signalservice.internal.push.TypingMessage;
 import org.whispersystems.signalservice.internal.push.Verified;
-import org.whispersystems.signalservice.internal.push.exceptions.GroupMismatchedDevicesException;
-import org.whispersystems.signalservice.internal.push.exceptions.GroupStaleDevicesException;
 import org.whispersystems.signalservice.internal.push.exceptions.InvalidUnidentifiedAccessHeaderException;
 import org.whispersystems.signalservice.internal.push.exceptions.MismatchedDevicesException;
 import org.whispersystems.signalservice.internal.push.exceptions.StaleDevicesException;
@@ -2558,52 +2562,53 @@ public class SignalServiceMessageSender {
 
       sendEvents.onMessageEncrypted();
 
-      try {
-        try {
+      MultiRecipientSendAuthorization multiRecipientAuth = story ? MultiRecipientSendAuthorization.Story.INSTANCE
+                                                                 : new MultiRecipientSendAuthorization.GroupSend(groupSendEndorsements.toFullToken());
 
-          SendGroupMessageResponse response = NetworkResultUtil.toGroupMessageSendLegacy(messageApi.sendGroupMessage(ciphertext, sealedSenderAccess, timestamp, online, urgent, story));
-          return transformGroupResponseToMessageResults(targetInfo.devices, response, content);
-        } catch (InvalidUnidentifiedAccessHeaderException |
-                 NotFoundException |
-                 GroupMismatchedDevicesException |
-                 GroupStaleDevicesException |
-                 ServerRejectedException |
-                 RateLimitException e) {
-          // Non-technical failures shouldn't be retried with socket
-          throw e;
-        } catch (WebSocketUnavailableException e) {
-          if (useRestFallback.getAsBoolean()) {
-            Log.i(TAG, "[sendGroupMessage][" + timestamp + "] Pipe unavailable, falling back... (" + e.getClass().getSimpleName() + ": " + e.getMessage() + ")");
-          } else {
-            Log.i(TAG, "[sendGroupMessage][" + timestamp + "] Pipe unavailable (" + e.getClass().getSimpleName() + ": " + e.getMessage() + ")");
-            throw e;
-          }
-        } catch (IOException e) {
-          if (useRestFallback.getAsBoolean()) {
-            Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Pipe failed, falling back... (" + e.getClass().getSimpleName() + ": " + e.getMessage() + ")");
-          } else {
-            Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Pipe failed (" + e.getClass().getSimpleName() + ": " + e.getMessage() + ")");
-            throw e;
-          }
-        }
+      RequestResult<MultiRecipientMessageResponse, MultiRecipientSendFailure> result = messageApi.sendGroupMessage(ciphertext, multiRecipientAuth, timestamp, online, urgent);
 
-        SendGroupMessageResponse response = socket.sendGroupMessage(ciphertext, sealedSenderAccess, timestamp, online, urgent, story);
-        return transformGroupResponseToMessageResults(targetInfo.devices, response, content);
-      } catch (GroupMismatchedDevicesException e) {
-        Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Handling mismatched devices. (" + e.getMessage() + ")");
-        for (GroupMismatchedDevices mismatched : e.getMismatchedDevices()) {
-          SignalServiceAddress address = new SignalServiceAddress(ServiceId.parseOrThrow(mismatched.getUuid()), Optional.empty());
-          handleMismatchedDevices(address, mismatched.getDevices());
+      if (result instanceof RequestResult.Success) {
+        MultiRecipientMessageResponse response = ((RequestResult.Success<MultiRecipientMessageResponse>) result).getResult();
+        return transformGroupResponseToMessageResults(targetInfo.devices, MessageApiKt.unsentTargets(response), content);
+      } else if (result instanceof RequestResult.NonSuccess) {
+        MultiRecipientSendFailure error = ((RequestResult.NonSuccess<MultiRecipientSendFailure>) result).getError();
+        if (error instanceof MismatchedDeviceException) {
+          MismatchedDeviceException mismatchedDeviceException = (MismatchedDeviceException) error;
+          Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Handling mismatched devices. (" + mismatchedDeviceException.getMessage() + ")");
+          for (MismatchedDeviceException.Entry entry : mismatchedDeviceException.getEntries()) {
+            SignalServiceAddress address = new SignalServiceAddress(ServiceId.fromLibSignal(entry.getAccount()));
+            MismatchedDevices    devices = MismatchedDevices.fromLibSignal(entry);
+            handleMismatchedDevices(address, devices);
+            if (entry.getStaleDevices().length > 0) {
+              StaleDevices staleDevices = StaleDevices.fromLibSignal(entry);
+              handleStaleDevices(address, staleDevices);
+            }
+          }
+        } else if (error instanceof RequestUnauthorizedException) {
+          Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Invalid access header.");
+          throw new InvalidUnidentifiedAccessHeaderException();
+        } else {
+          throw new IOException("Unknown multi-recipient send failure: " + error.getClass().getSimpleName());
         }
-      } catch (GroupStaleDevicesException e) {
-        Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Handling stale devices. (" + e.getMessage() + ")");
-        for (GroupStaleDevices stale : e.getStaleDevices()) {
-          SignalServiceAddress address = new SignalServiceAddress(ServiceId.parseOrThrow(stale.getUuid()), Optional.empty());
-          handleStaleDevices(address, stale.getDevices());
+      } else if (result instanceof RequestResult.RetryableNetworkError) {
+        RequestResult.RetryableNetworkError retryableError = (RequestResult.RetryableNetworkError) result;
+        IOException                         exception      = retryableError.getNetworkError();
+        if (exception instanceof RetryLaterException) {
+          throw exception;
+        } else if (retryableError.getRetryAfter() != null && retryableError.getRetryAfter().toMillis() > 0) {
+          throw new RetryNetworkException(retryableError.getRetryAfter().toMillis(), exception);
+        } else {
+          throw exception;
+        }
+      } else if (result instanceof RequestResult.ApplicationError) {
+        Throwable cause = ((RequestResult.ApplicationError) result).getCause();
+        if (cause instanceof IOException) {
+          throw (IOException) cause;
+        } else if (cause instanceof RuntimeException) {
+          throw (RuntimeException) cause;
+        } else {
+          throw new UnknownGroupSendException(cause);
         }
-      } catch (InvalidUnidentifiedAccessHeaderException e) {
-        Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Invalid access header. (" + e.getMessage() + ")");
-        throw e;
       }
 
       Log.w(TAG, "[sendGroupMessage][" + timestamp + "] Attempt failed (i = " + i + ")");
@@ -2656,9 +2661,7 @@ public class SignalServiceMessageSender {
     }
   }
 
-  private List<SendMessageResult> transformGroupResponseToMessageResults(Map<SignalServiceAddress, List<Integer>> recipients, SendGroupMessageResponse response, Content content) {
-    Set<ServiceId> unregistered = response.getUnsentTargets();
-
+  private List<SendMessageResult> transformGroupResponseToMessageResults(Map<SignalServiceAddress, List<Integer>> recipients, Set<ServiceId> unregistered, Content content) {
     List<SendMessageResult> failures = unregistered.stream()
                                                    .map(SignalServiceAddress::new)
                                                    .map(SendMessageResult::unregisteredFailure)

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/groupsv2/GroupSendEndorsements.kt

@@ -26,8 +26,12 @@ data class GroupSendEndorsements(
   private val expiration: Instant by lazy { Instant.ofEpochMilli(expirationMs) }
   private val combinedEndorsement: GroupSendEndorsement by lazy { GroupSendEndorsement.combine(endorsements.values) }
 
+  fun toFullToken(): GroupSendFullToken {
+    return combinedEndorsement.toFullToken(groupSecretParams, expiration)
+  }
+
   fun serialize(): ByteArray {
-    return combinedEndorsement.toFullToken(groupSecretParams, expiration).serialize()
+    return toFullToken().serialize()
   }
 
   fun forIndividuals(addresses: List<SignalServiceAddress>): List<GroupSendFullToken?> {

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/message/MessageApi.kt

@@ -5,16 +5,21 @@
 
 package org.whispersystems.signalservice.api.message
 
+import kotlinx.coroutines.runBlocking
 import org.signal.core.models.ServiceId
+import org.signal.libsignal.net.MultiRecipientMessageResponse
+import org.signal.libsignal.net.MultiRecipientSendAuthorization
+import org.signal.libsignal.net.MultiRecipientSendFailure
+import org.signal.libsignal.net.RequestResult
+import org.signal.libsignal.net.UnauthMessagesService
+import org.signal.libsignal.net.getOrError
 import org.whispersystems.signalservice.api.NetworkResult
 import org.whispersystems.signalservice.api.crypto.SealedSenderAccess
 import org.whispersystems.signalservice.api.websocket.SignalWebSocket
 import org.whispersystems.signalservice.internal.post
 import org.whispersystems.signalservice.internal.push.OutgoingPushMessageList
-import org.whispersystems.signalservice.internal.push.SendGroupMessageResponse
 import org.whispersystems.signalservice.internal.push.SendMessageResponse
 import org.whispersystems.signalservice.internal.put
-import org.whispersystems.signalservice.internal.putCustom
 import org.whispersystems.signalservice.internal.websocket.WebSocketRequestMessage
 import org.whispersystems.signalservice.internal.websocket.WebsocketResponse
 
@@ -70,24 +75,14 @@ class MessageApi(
   }
 
   /**
-   * Sends a common message to multiple recipients and requires some form of [sealedSenderAccess] unless it's a story.
-   *
-   * PUT /v1/messages/multi_recipient?ts=[timestamp]&online=[online]&urgent=[urgent]&story=[story]
-   * - 200: Success
-   * - 400: Message specified delivery to the same recipient device multiple times
-   * - 401: Message is not a story and [sealedSenderAccess] is missing or incorrect
-   * - 404: Message is not a story and some of the recipients are not registered Signal users
-   * - 409: Incorrect set of devices supplied for some recipients
-   * - 410: Stale devices supplied for some recipients
+   * Sends a common message to multiple recipients using the libsignal-net [UnauthMessagesService].
    */
-  fun sendGroupMessage(body: ByteArray, sealedSenderAccess: SealedSenderAccess, timestamp: Long, online: Boolean, urgent: Boolean, story: Boolean): NetworkResult<SendGroupMessageResponse> {
-    val request = WebSocketRequestMessage.putCustom(
-      path = "/v1/messages/multi_recipient?ts=$timestamp&online=${online.toQueryParam()}&urgent=${urgent.toQueryParam()}&story=${story.toQueryParam()}",
-      body = body,
-      headers = mapOf("content-type" to "application/vnd.signal-messenger.mrm")
-    )
-
-    return NetworkResult.fromWebSocket { unauthWebSocket.request(request, sealedSenderAccess) }
+  fun sendGroupMessage(body: ByteArray, auth: MultiRecipientSendAuthorization, timestamp: Long, online: Boolean, urgent: Boolean): RequestResult<MultiRecipientMessageResponse, MultiRecipientSendFailure> {
+    return runBlocking {
+      unauthWebSocket.runCatchingWithUnauthChatConnection { chatConnection ->
+        UnauthMessagesService(chatConnection).sendMultiRecipientMessage(body, timestamp, auth, online, urgent)
+      }.getOrError()
+    }
   }
 
   /**
@@ -103,3 +98,7 @@ class MessageApi(
 
   private fun Boolean.toQueryParam(): String = if (this) "true" else "false"
 }
+
+fun MultiRecipientMessageResponse.unsentTargets(): Set<ServiceId> {
+  return unregisteredIds.mapTo(HashSet(unregisteredIds.size)) { ServiceId.fromLibSignal(it) }
+}

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/push/exceptions/RetryNetworkException.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.signalservice.api.push.exceptions
+
+import java.io.IOException
+
+/**
+ * Wraps an exception that does not hold retry after data so that it *can* have retry after data.
+ */
+class RetryNetworkException(val retryAfterMs: Long, cause: Throwable) : IOException(cause)

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/push/exceptions/UnknownGroupSendException.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.signalservice.api.push.exceptions
+
+/**
+ * Wraps a [org.signal.libsignal.net.RequestResult.ApplicationError]'s cause in a named
+ * [RuntimeException] so it is more identifiable.
+ */
+class UnknownGroupSendException(cause: Throwable) : RuntimeException(cause)

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/internal/push/MismatchedDevices.java

@@ -1,13 +1,15 @@
-/**
- * Copyright (C) 2014-2016 Open Whisper Systems
- *
- * Licensed according to the LICENSE file in this repository.
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 package org.whispersystems.signalservice.internal.push;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import org.signal.libsignal.net.MismatchedDeviceException;
+
+import java.util.ArrayList;
 import java.util.List;
 
 public class MismatchedDevices {
@@ -24,4 +26,21 @@ public class MismatchedDevices {
   public List<Integer> getExtraDevices() {
     return extraDevices;
   }
+
+  public static MismatchedDevices fromLibSignal(MismatchedDeviceException.Entry entry) {
+    MismatchedDevices result = new MismatchedDevices();
+
+    result.missingDevices = toList(entry.getMissingDevices());
+    result.extraDevices   = toList(entry.getExtraDevices());
+
+    return result;
+  }
+
+  private static List<Integer> toList(int[] array) {
+    List<Integer> list = new ArrayList<>(array.length);
+    for (int value : array) {
+      list.add(value);
+    }
+    return list;
+  }
 }

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java

@@ -15,11 +15,11 @@ import org.signal.core.util.Hex;
 import org.signal.libsignal.protocol.InvalidKeyException;
 import org.signal.libsignal.protocol.logging.Log;
 import org.signal.storageservice.storage.protos.groups.AvatarUploadAttributes;
+import org.signal.storageservice.storage.protos.groups.ExternalGroupCredential;
 import org.signal.storageservice.storage.protos.groups.Group;
 import org.signal.storageservice.storage.protos.groups.GroupChange;
 import org.signal.storageservice.storage.protos.groups.GroupChangeResponse;
 import org.signal.storageservice.storage.protos.groups.GroupChanges;
-import org.signal.storageservice.storage.protos.groups.ExternalGroupCredential;
 import org.signal.storageservice.storage.protos.groups.GroupJoinInfo;
 import org.signal.storageservice.storage.protos.groups.GroupResponse;
 import org.signal.storageservice.storage.protos.groups.Member;
@@ -79,11 +79,8 @@ import org.whispersystems.signalservice.internal.configuration.SignalUrl;
 import org.whispersystems.signalservice.internal.crypto.AttachmentDigest;
 import org.whispersystems.signalservice.internal.push.exceptions.ForbiddenException;
 import org.whispersystems.signalservice.internal.push.exceptions.GroupExistsException;
-import org.whispersystems.signalservice.internal.push.exceptions.GroupMismatchedDevicesException;
 import org.whispersystems.signalservice.internal.push.exceptions.GroupNotFoundException;
 import org.whispersystems.signalservice.internal.push.exceptions.GroupPatchNotAcceptedException;
-import org.whispersystems.signalservice.internal.push.exceptions.GroupStaleDevicesException;
-import org.whispersystems.signalservice.internal.push.exceptions.InvalidUnidentifiedAccessHeaderException;
 import org.whispersystems.signalservice.internal.push.exceptions.MismatchedDevicesException;
 import org.whispersystems.signalservice.internal.push.exceptions.NotInGroupException;
 import org.whispersystems.signalservice.internal.push.exceptions.StaleDevicesException;
@@ -135,12 +132,10 @@ import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509TrustManager;
 
 import kotlin.Pair;
-
 import okhttp3.Call;
 import okhttp3.ConnectionPool;
 import okhttp3.ConnectionSpec;
 import okhttp3.Dns;
-import okhttp3.Headers;
 import okhttp3.HttpUrl;
 import okhttp3.Interceptor;
 import okhttp3.MediaType;
@@ -533,62 +528,6 @@ public class PushServiceSocket {
     return JsonUtil.fromJson(responseText, RegisterAsSecondaryDeviceResponse.class);
   }
 
-  public SendGroupMessageResponse sendGroupMessage(byte[] body, @Nonnull SealedSenderAccess sealedSenderAccess, long timestamp, boolean online, boolean urgent, boolean story)
-      throws NonSuccessfulResponseCodeException, PushNetworkException, MalformedResponseException
-  {
-    ServiceConnectionHolder connectionHolder = (ServiceConnectionHolder) getRandom(serviceClients, random);
-
-    String path = String.format(Locale.US, GROUP_MESSAGE_PATH, timestamp, online, urgent, story);
-
-    Request.Builder requestBuilder = new Request.Builder();
-    requestBuilder.url(String.format("%s%s", connectionHolder.getUrl(), path));
-    requestBuilder.put(RequestBody.create(MediaType.get("application/vnd.signal-messenger.mrm"), body));
-    requestBuilder.addHeader(sealedSenderAccess.getHeaderName(), sealedSenderAccess.getHeaderValue());
-
-    if (signalAgent != null) {
-      requestBuilder.addHeader("X-Signal-Agent", signalAgent);
-    }
-
-    if (connectionHolder.getHostHeader().isPresent()) {
-      requestBuilder.addHeader("Host", connectionHolder.getHostHeader().get());
-    }
-
-    Call call = connectionHolder.getUnidentifiedClient().newCall(requestBuilder.build());
-
-    synchronized (connections) {
-      connections.add(call);
-    }
-
-    try (Response response = call.execute()) {
-      switch (response.code()) {
-        case 200:
-          return readBodyJson(response.body(), SendGroupMessageResponse.class);
-        case 401:
-          throw new InvalidUnidentifiedAccessHeaderException();
-        case 404:
-          throw new NotFoundException("At least one unregistered user in message send.");
-        case 409:
-          GroupMismatchedDevices[] mismatchedDevices = readBodyJson(response.body(), GroupMismatchedDevices[].class);
-          throw new GroupMismatchedDevicesException(mismatchedDevices);
-        case 410:
-          GroupStaleDevices[] staleDevices = readBodyJson(response.body(), GroupStaleDevices[].class);
-          throw new GroupStaleDevicesException(staleDevices);
-        case 508:
-          throw new ServerRejectedException();
-        default:
-          throw new NonSuccessfulResponseCodeException(response.code());
-      }
-    } catch (PushNetworkException | NonSuccessfulResponseCodeException | MalformedResponseException e) {
-      throw e;
-    } catch (IOException e) {
-      throw new PushNetworkException(e);
-    } finally {
-      synchronized (connections) {
-        connections.remove(call);
-      }
-    }
-  }
-
   public SendMessageResponse sendMessage(OutgoingPushMessageList bundle, @Nullable SealedSenderAccess sealedSenderAccess, boolean story)
       throws IOException
   {

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/internal/push/SendGroupMessageResponse.java

@@ -1,36 +0,0 @@
-package org.whispersystems.signalservice.internal.push;
-
-import com.fasterxml.jackson.annotation.JsonProperty;
-
-import org.signal.libsignal.protocol.logging.Log;
-import org.signal.core.models.ServiceId;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public class SendGroupMessageResponse {
-
-  private static final String TAG = SendGroupMessageResponse.class.getSimpleName();
-
-  // Contains serialized ServiceIds
-  @JsonProperty
-  private String[] uuids404;
-
-  public SendGroupMessageResponse() {}
-
-  public Set<ServiceId> getUnsentTargets() {
-    String[]       uuids      = uuids404 != null ? uuids404 : new String[0];
-    Set<ServiceId> serviceIds = new HashSet<>(uuids.length);
-
-    for (String raw : uuids) {
-      ServiceId parsed = ServiceId.parseOrNull(raw);
-      if (parsed != null) {
-        serviceIds.add(parsed);
-      } else {
-        Log.w(TAG, "Failed to parse ServiceId!");
-      }
-    }
-
-    return serviceIds;
-  }
-}

lib/libsignal-service/src/main/java/org/whispersystems/signalservice/internal/push/StaleDevices.java

@@ -1,13 +1,15 @@
-/**
- * Copyright (C) 2014-2016 Open Whisper Systems
- *
- * Licensed according to the LICENSE file in this repository.
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 package org.whispersystems.signalservice.internal.push;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import org.signal.libsignal.net.MismatchedDeviceException;
+
+import java.util.ArrayList;
 import java.util.List;
 
 public class StaleDevices {
@@ -18,4 +20,15 @@ public class StaleDevices {
   public List<Integer> getStaleDevices() {
     return staleDevices;
   }
+
+  public static StaleDevices fromLibSignal(MismatchedDeviceException.Entry entry) {
+    StaleDevices  result = new StaleDevices();
+    int[]         stale  = entry.getStaleDevices();
+    List<Integer> list   = new ArrayList<>(stale.length);
+    for (int value : stale) {
+      list.add(value);
+    }
+    result.staleDevices = list;
+    return result;
+  }
 }