diff --git a/doc/source/development/notebooks/processor_examples/regex.ipynb b/doc/source/development/notebooks/processor_examples/regex.ipynb
index 4f2e9ba34..f933f9e62 100644
--- a/doc/source/development/notebooks/processor_examples/regex.ipynb
+++ b/doc/source/development/notebooks/processor_examples/regex.ipynb
@@ -63,6 +63,9 @@
     "rule_path.mkdir(exist_ok=True)\n",
     "rule_file = rule_path / \"data-stream.yml\"\n",
     "\n",
+    "if rule_file.exists():\n",
+    "    rule_file.unlink()\n",
+    "\n",
     "processor_config = {\n",
     "    \"myconcatenator\":{   \n",
     "        \"type\": \"concatenator\",\n",
@@ -71,11 +74,12 @@
     "        }\n",
     "    }\n",
     "\n",
-    "concatenator = Factory.create(processor_config)\n",
-    "\n",
     "def concat_with_rule(rule_yaml):\n",
     "    mydocument = deepcopy(document)\n",
+    "    if rule_file.exists():\n",
+    "        rule_file.unlink()\n",
     "    rule_file.write_text(rule_yaml)\n",
+    "    concatenator = Factory.create(processor_config)\n",
     "    print(f\"before: {mydocument}\")\n",
     "    concatenator.process(mydocument)\n",
     "    print(f\"after: {mydocument}\")\n",
@@ -95,10 +99,20 @@
    "execution_count": 3,
    "metadata": {},
    "outputs": [
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "[Deprecated]: regex_fields are no longer necessary. Use Lucene regex annotation.\n"
+     ]
+    },
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
+      "\n",
+      "\n",
+      "[Deprecation warning]: regex_fields are no longer necessary. Use lucene regex annotation.\n",
       "before: {'data_stream': {'dataset': 'windows', 'namespace': 'devopslab', 'type': 'logs'}, '_op_type': 'create'}\n",
       "after: {'data_stream': {'dataset': 'windows', 'namespace': 'devopslab', 'type': 'logs'}, '_op_type': 'create', '_index': 'logs-windows-devopslab'}\n",
       "True\n"
@@ -120,7 +134,7 @@
     "  overwrite_target: false\n",
     "  delete_source_fields: false\n",
     "\"\"\"\n",
-    "    \n",
+    "\n",
     "concat_with_rule(rule_yaml)\n"
    ]
   },
@@ -147,7 +161,7 @@
     }
    ],
    "source": [
-    "rule_yaml2 = \"\"\"---\n",
+    "rule_yaml = \"\"\"---\n",
     "filter: 'data_stream.type: \"/.*lo.*/\"'    \n",
     "concatenator:\n",
     "  source_fields:\n",
@@ -159,7 +173,7 @@
     "  overwrite_target: false\n",
     "  delete_source_fields: false\n",
     "\"\"\"\n",
-    "concat_with_rule(rule_yaml2)\n"
+    "concat_with_rule(rule_yaml)\n"
    ]
   }
  ],