Trigger on delete.

app/Api/V1/Controllers/TransactionController.php

@@ -26,6 +26,7 @@ namespace FireflyIII\Api\V1\Controllers;
 
 use FireflyIII\Api\V1\Requests\TransactionStoreRequest;
 use FireflyIII\Api\V1\Requests\TransactionUpdateRequest;
+use FireflyIII\Events\DestroyedTransactionGroup;
 use FireflyIII\Events\StoredTransactionGroup;
 use FireflyIII\Events\UpdatedTransactionGroup;
 use FireflyIII\Exceptions\DuplicateTransactionException;
@@ -145,6 +146,8 @@ class TransactionController extends Controller
     public function delete(TransactionGroup $transactionGroup): JsonResponse
     {
         $this->repository->destroyGroup($transactionGroup);
+        // trigger just after destruction
+        event(new DestroyedTransactionGroup($transactionGroup));
 
         return response()->json([], 204);
     }

app/Generator/Webhook/StandardMessageGenerator.php

@@ -41,7 +41,7 @@ use Symfony\Component\HttpFoundation\ParameterBag;
  */
 class StandardMessageGenerator implements MessageGeneratorInterface
 {
-    private int        $version = 1;
+    private int        $version = 0;
     private User       $user;
     private Collection $objects;
     private int        $trigger;

app/Handlers/Events/DestroyedGroupEventHandler.php

@@ -0,0 +1,54 @@
+<?php
+/*
+ * DestroyedGroupEventHandler.php
+ * Copyright (c) 2020 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace FireflyIII\Handlers\Events;
+
+
+use FireflyIII\Events\DestroyedTransactionGroup;
+use FireflyIII\Events\RequestedSendWebhookMessages;
+use FireflyIII\Generator\Webhook\MessageGeneratorInterface;
+use FireflyIII\Models\Webhook;
+use Illuminate\Support\Collection;
+use Log;
+
+/**
+ * Class DestroyedGroupEventHandler
+ */
+class DestroyedGroupEventHandler
+{
+    /**
+     * @param DestroyedTransactionGroup $destroyedGroupEvent
+     */
+    public function triggerWebhooks(DestroyedTransactionGroup $destroyedGroupEvent): void
+    {
+        Log::debug('DestroyedTransactionGroup:triggerWebhooks');
+        $group = $destroyedGroupEvent->transactionGroup;
+        $user  = $group->user;
+        /** @var MessageGeneratorInterface $engine */
+        $engine = app(MessageGeneratorInterface::class);
+        $engine->setUser($user);
+        $engine->setObjects(new Collection([$group]));
+        $engine->setTrigger(Webhook::TRIGGER_DESTROY_TRANSACTION);
+        $engine->generateMessages();
+
+        event(new RequestedSendWebhookMessages);
+    }
+}

app/Helpers/Webhook/Sha3SignatureGenerator.php

@@ -29,7 +29,7 @@ use JsonException;
  */
 class Sha3SignatureGenerator implements SignatureGeneratorInterface
 {
-    private int $version = 1;
+    private int $version = 0;
 
     /**
      * @inheritDoc